Jeremy Paxton, the eco-conscious holiday-home developer, is at it again. His Lower Mill Estate, an enclave of upmarket waterside holiday hideaways on a private nature reserve in the Cotswolds, was hailed as a beacon of rural modernism when he launched its programme of multimillion-pound Landmark Houses, designed by top architects, in 2005. This week, Paxton launches a new range of “affordable” homes. That means price tags of between £500,000 and £750,000 to you and me.

The estate, near the village of Somerford Keynes, about five miles from Cirencester, may sound olde England, but it is anything but. In the early 1990s, Paxton, 47, a water-skiing enthusiast and publishing tycoon turned developer, spotted the 600-acre area of flooded former gravel pits from his helicopter. As an industrial site, the area counted as brownfield land. So, 12 years ago, he bought it, won planning permission – subject to the homes not being lived in all year round – and began to develop his exclusive scheme.

The estate comes with attractive wildlife and a designer spa (when the latter opened last year, he allegedly put the noses of high-profile neighbours such as Liz Hurley and Zara Phillips out of joint by banning nonresidents). The homes all have to stand empty for one month a year, between January 6 and February 5, but the wildlife stays put. There are otters, owls, water voles and European beavers – the introduction of the last of these cost Paxton £500,000.

So far, 176 homes have been built and another 20 of the turnkey properties are under way, out of an eventual total of 575. It was all a bit traditional and Cotswoldy at first, but it became more modern and ambitious under the direction of Paxton’s chief architect, Richard Reid. The latest four- and five-bedroom, mainly three-storey houses are selling for between £850,000 and £1.1m. If that is what people pay for second homes round there, then £500,000+ might look affordable.

Only one of the big, unconventional Landmark Houses has actually materialised, despite the razzmatazz that greeted their launch. The £2m prototype, the Reid-designed Somerford Villa, is now in private hands, although a Monaco-based millionaire is said to have ordered a Sarah Featherstone design, inspired by the bee orchid, to house his erotic art collection. So, to stop his architectural team twiddling their thumbs, Paxton has put them onto the “affordable” stuff. What he has in mind is three- or fourbed properties that you can collect, like pieces of contemporary art.

“It’s not a property development, it’s an art project,” he enthuses. “Imagine a house by Will Alsop for only £500,000.” Actually, there are homes at Lower Mill that really are affordable: I found a two-bedroom terraced cottage in the Mill Village enclave being resold for a mere £165,000 and a four-bedroom detached house for £275,000. Two later, bigger homes in Clearwater Village have price tags of £425,000 and £825,000. If you want a new house, two-bedders now start at £310,000.

Paxton still hankers after high architectural style. “This isn’t part of the Landmark House programme, though it is inspired by it,” he says of his latest proposal. “There are eight of them. They will all be built within two years. We’re already getting people pawing at the door.” The latest houses are designed to sit in the water, like inhabited jetties. The biggest name on the design roster is Alsop. Famous for his bold, dramatic designs, he won the Stirling prize in 2000 for Peckham Library, essentially a decorated glass box. I like his concept of putting photovoltaic panels – a green method of generating electricity – on tall stalks so they shade the house like giant sunflowers.

Piers Gough, best know for his urban regeneration work, and Featherstone are back; other architects involved, such as Andy Ramus, 33, are less well known. Some of the designs are a great deal more conventional than Alsop’s – Paxton appears to be hedging his bets.

So, this is the acid test: is it price or style that sets the bar at Lower Mill Estate? Paxton, as ever, is bigging it up: “They will all be growing from nature, not landing on it; they are being built within the most significant wetland habitat remaining on the estate; and they all overlook nature reserves of European significance. They are homes that will allow their owners to chill out among nature and start making memories.”

Well, perhaps, but these are just top-end holiday homes with added otters, not Xanadu. Still, there are more than enough pastiche country cottages about. It could be that the countryside could benefit from a dose of Will Alsop. If anyone can do it, Paxton can2

- Lower Mill Estate, 01285 869489, www.lowermillestate.com

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