Solid oak flooring.

Reclaimed oak parquet (on eBay, for example) is a lot cheaper

Oh indeed. But he doesn't want parquet. Which is cheaper than planks because it is all offcuts. ;-)

The stuff Wickes sold about 10 years ago, came in packs 1.2 metres long but out of 21 packs I only found one piece of flooring that was 1200mm, and a lot of 300mm ones.

Also it wasn't very good 'hardwood', very easy to scratch or dent. It was £30 /sq metre, which cost me £630 and for another £200 I could have got longer lengths and consistent species which the Wickes stuff wasn't, it looks like their Chinese supplier has used offcuts from other work to make the stuff.

Also, I glued mine into long, wide 'planks'. The wickes metal clips are useless, but you need to allow for expansion and contraction, so gluing onto a solid floor is not advised - the different species of wood move at different amounts. A couple of the shorter sections that I glued together to make larger planks have split slightly at the end during very dry weather.

Conclusion - use some good quality engineered interlocking planking. £2000 is too cheap. decent flooring will be that price alone, plus labour plus skirtings/frames.

Yup, does seem optimistic for solid wood.

About 18 months ago I did:

Try used oak flooring planks.

NT

Mmmm I have approx 40m2 solid oak t & g glued straight to concrete here. It's not developed any issues in 15+ years