The Plettenberg, Plettenberg Bay, South Africa

Find yourself at the end of a cul-de-sac with such a spectacular view of the sea and you may be forgiven for being distracted from the unremarkable white square building. But take a closer look at the dark wooden window frames and clean lines and you could credit the hotel with an air of understated Californian cool. Enter the discreet main door of The Plettenberg, and you get an instant 180º hit of the hotel's communal areas – homely sitting room, contemporary bar, seaside lounge, restaurant and terrace beyond – then a small swivel round to the right and you're at the low-key front desk. It offers all the service of an international five-star hotel, but without the pomp – the first indication that you are at an establishment where the army of smiling staff is gentle enough so as not to detract from the peaceful atmosphere: probably the key ingredient in their high level of hospitality. There are 100 staff in high season, a huge percentage of who have been there since the get-go, a decade ago.

The buzzwords when describing any of Liz McGrath's hotels would be spacious and airy, eschewing minimalism and gimmicks for traditional comforts. The hands-on hotelier first opened The Plettenberg in 1987 when she took a run-down 19th-century seaside stay and breathed a fresh lease of life into it, and the surrounding area. As someone who has stayed in over 50 Relais & Chateaux hotels in Europe, when her husband passed away she decided to draw from her well-travelled background, and create her own places to stay.

McGrath's design philosophy is based on three S words: style, simplicity and seclusion, and her initial fondness for chintz has long since evolved and favouring delicate colour schemes, such as apricot, lemon and cobalt blue, she strives for an environment befitting a mansion in the home counties. Indeed, the sitting room at The Plettenberg is probably not too dissimilar from the one many of its well-heeled guests have at home; a dark wood cabinet displays fine china, heavy silk drapes, brass lamp fittings, an open fire – there's even a framed snapshot of the Duke of Edinburgh.

In the lounge, where French doors lead to the terrace and pool, the theme is more complementary to the hotel's coastal location; wicker furniture is covered in cushions adorned with cutesy starfish and shell motifs, there are nautical lamps, and a seaside-accented trompe l'oeil on the walls. And the accoutrement de resistance? A telescope for the whale-watching months.

The focus of the restaurant, Sand at the Plettenberg, is more on fine dining than fancy decor, and it's the cocktail lounge next door which steals the design headlines. It has introduced acid lime and bright turquoise to the palette as well as a savvy blend of textures; glass, leather, marble, oak and sandy surfaces blend with mood lighting and modern images to provide a refreshing enclave of contemporary chic. For a unique wining and dining experience, The Plettenberg also offers the chance to have a cosy dinner à deux in their cellar, surrounded by hundreds of the South African wines from their award-winning list.

The main hotel has 21 rooms, and across the road in the recently added Blue Wing there are 15 more suites and doubles, as well as another cliff-side pool where the water appears to melt into the sea's horizon. Each bedroom is declared as individually styled, which means a subtle change in colour schemes, and fresh soft furnishings. Fabrics are sure to give Osborne & Little purists a thrill, although interestingly the designs are all homegrown. McGrath explains that the economy's isolation in past years meant that importing fabrics was not an option, and as a result nurtured a real 'do-it-yourself' culture, as she calls it. Manufacturers would copy British-made patterns and as a result the South African supplies became very competitive. Liz is lauded for her insistence at using local suppliers wherever possible, and while she pays a full-time decor consultant who helps source exactly the fabric or lampshade she craves, it is her eye that decides the look. "I'm addicted to building, decorating, gardening and food," she enthuses. "And being a hotelier fuels all my addictions, and every year I refurbish."

Recognising the penchant for homes from homes at the top end of the tourist market, there are two private beach villas at the Plettenberg. Completely separate and self-contained, they boast kitchens and dining rooms, expansive living rooms with all the home-entertainment trimmings. The private pool and terrace with greedy views of Plett's magnificent sprawling beach is what makes its guests feel like rockstars – but then at R12,000 a night for the three-bedroomed Lookout Villa, guests are playing A-list prices for the privilege. (After all, this is where the Beckhams stayed.) As the hotel itself doesn't allow children under 12, the villas also provide an opportunity to indulge in McGrath's silver service standard while on a family holiday. And, if the ankle biters get too exhausting, parents can always nip over to the Carchelle spa to treat themselves to one of the Decléor treatments.

Anywhere where the rack rates can be compared to London prices is likely to lure the silver pound, and among the 50% of their guests whom are Brits, you'll spy a few lord and ladies in the guestbook. But the biggest growth has been among the Irish, 75% of whom are honeymooners. A nation known for having the gift of the gab, the manager Nigel Pace remarks: "I think they go back and spread the word and do the marketing for us." And with an airport planned for Plett, it will mean an influx of 737-bound visitors rather than just those who fly to George or Port Elizabeth and plot their stay as part of their Garden Route escapades, so the Plettenberg's track record of almost-full occupancy seems more secure as ever.