zone 2 light fittings

I have IKEA ones. They don't do my model any more, but they might still do some suitable, and they were very cheap.

If you can't find anything specifically labelled as Zone 2, any IPX4 or higher rated fitting with no exposed metal parts should do. When searching, check in the outdoor lighting sections too, again checking for IPX4 (or better) with no exposed metalwork.

The IKEA ones would have been under £20, maybe as low as £10, but I don't recall now.

That's true. I find lighting which is both aesthetically pleasing and designed with good technical compitence (e.g. IPx4, or low energy compatible, or whatever other quite reasonable requirements you might have) is very hard to find. Many of my own house lights I have made myself as a consequence.