B&B and Beyond: Trevose Harbour House, St Ives

As the Sunrise, it was cramped and old-fashioned. Now it's a sanctuary of space and Fifties style, says Sarah Baxter

Trevose Harbour House was built around 1850 – but is now most definitely of 2013. This whitewashed mid-terrace, deep in the cutesy muddle of St Ives, opened in March after a painstaking year of total transformation, blossoming from old-school B&B (called the Sunrise) to drool-cool five-star guesthouse. The only thing the new owners didn't ditch when they started were the incumbent Ercol tables and chairs – which part-inspired Trevose's new mid-century-meets-contemporary-coast style. At a time when "boutique" might be bandied by any small lodging that paints a wall purple, Trevose reclaims the word, and cranks it up to 11.

The Bed

As Sunrise B&B, seven bedrooms were squeezed into this slender home. As Trevose, there's an extra storey, lowered floors, raised ceilings, a converted shed – and only six bedrooms. Each room is different, but with the same fresh blue-white tones and Fifties chic. The Suite is the star, a top-floor eyrie, with sea views, sink-in sheepskin rug, and loungy chaise longue. Its huge bathroom has a roll-top tub under Velux windows – light candles and open the blind to bathe beneath the stars, or gaze at St Ives from the separate monsoon shower.

The Terrace Deluxe, an annexe at the back, still sneaks harbour views and is inherently romantic: three marriage proposals have been made here in just six months. Rooms 1 and 2 (shower-only) gaze into The Warren alleyway; 3 (with roll-top bath) and 4 (the smallest) have bay windows overlooking the sea.

All six rooms have the same high-end finish: large Hypnos beds, iPod docks, Neal's Yard toiletries; local artwork, mid-century modern chairs, contemporary fabrics.

The Breakfast

Simple, delicious and everything you'd expect from a VisitBritain Gold-awarded breakfast: organic, locally sourced, home-made where possible. A coffee machine dispenses espresso and there's a banquet of granola, Cornish cheese and pastries. Cooked choices range from full English to potato scones; meats come from a traditional St Just butcher, salmon from the Penryn Smokehouse. There are plans to sponsor some Cornish bees, so that the fresh breads can be slathered with Trevose's own honey.

The Hosts

Unlike many "let's move to the country"-ites who think it'll be "fun!" to open a B&B, Angela and Olivier Noverraz actually know what they're doing. Having met at Switzerland's prestigious Ecole Hôtelière de Lausanne, they've since worked in some of Europe's top hotels. Trevose, their baby, is the distillation of all that experience, and a manifestation of their considerable personal style.

Ollie project-managed the build; Angela, pregnant for half of it, was in charge of interior design. Their attention to detail is obsessive, but they know that positioning themselves at the higher end of the market means delivering on every aspect, every time. "We don't take our rates for granted," says Angela, "we strive to exceed guests' expectations."

The Weekend

If it's sunny, hit St Ives' beaches; surf, kayak and paddleboard lessons can be arranged (01736 793938; stivessurfschool.co.uk). The al fresco sculptures at the Barbara Hepworth Gallery (01736 796226; tate.org.uk; £6) look best in fine weather, while the Tate St Ives (£7 or £11 with Hepworth Gallery) is good for damper days.

For an indulgent leg-stretch, tackle the six-mile section of South West Coast Path to Zennor, ending at the Gurnard's Head pub for lunch (01736 796928; gurnardshead.co.uk); look out for seals en route.

Everything else, it seems, is about an hour away – the Eden Project, Padstow, the Lost Gardens of Heligan – making St Ives a handy Cornish base.

The Pit-stop

St Ives isn't short of eateries, although Angela and Ollie direct most guests to the Porthminster Café & Restaurant (01736 795352; porthminstercafe.co.uk) – as much for its beach location as its menu. Seafood rules here, from starters of Fowey mussels (£10.95) and blow-torched mackerel (£8.95), to mains of monkfish curry (£19.95) and linguine with Cornish crab (£14.95).

Also recommended is Porthmeor Beach Café (01736 793 366; porthmeor-beach.co.uk/cafe), which is located on the right side of St Ives for watching sunset. Blas Burger Works (01736 797272; blasburgerworks.co.uk), just along The Warren, does quality fast food.

Trevose has an honesty bar and Ollie can also prepare a gourmet Cream Tea hamper (£60): a wicker basket packed with Ottolenghi-esque salads, pork pies, scones, jam and champagne.

The Essentials

22 The Warren, St Ives, Cornwall TR26 2EA (01736 793267; trevosehouse.co.uk). Rooms start at £135, including breakfast. Limited parking available (£7/day).