Has anyone any experience of using solar slates or tiles as opposed to panels for hot water production? I have found one manufacturer/distributor on the internet with useful information - Solex Energy Ltd. The National Trust use solar slates but their projects will be considerably larger than ours. Help appreciated.

Jane - you can get Solar hot water 'slates'
http://www.solexenergy.co.uk/
The design is:

Lay a grid over an insulated roofing felt (insulated underneath) then install glass/plastic slates on top.

The collector performance is low and there may be condensation issues as the void is not sealed (or even it is, the sealing is on a roof, not a factory).

WIll, like anys system produce hot water in summenr, but little chance in winter months (realy need evacuated tubes for a longer 'solar season')

As you effectively build the collector on the roof the price relatively low, but you need more, etc.

I think they are a very interesting idea and may appeal to planning officers, but I would rather spend my money on a pannel that has a reasonable expectation of lasting 20-30 years

Thanks for the comments and advice. Our plan was to use a ground source heat pump for the underfloor heating and maybe a solar solution for the hot water in the summer. I must admit that I was quite fascinated by the Solex Energy solution since we have to re-roof quite a large outbuilding (currently corrugated sheets) which could also house the heat pump compressor. I'm not keen on the look of solar panels but I think any planning officer would prefer them to the rusty sheets that are there at present! No, forget I said that, nothing is certain in the planning world.