It isn't clear from the description but these toilet seats are solid oak and really good quality, with thick wood, strong hinges, full width hinge bar and all the necessary fixings. I know because I've just fitted one and the box says 'Solid Oak'. It looks great so I've just bought another.
B&Q's oak seats are more expensive with much lower quality and ratings. Screwfix sells Oak veneer seats for more money as does Amazon. Nothing cheaper on Ebay either. John Lewis charges an astonishing £65 for its solid oak seat which gets very dodgy reviews. You can reserve online and then check these out instore, which is what I did.
My guess, and it is only a guess, is that the website description is ambiguous (it says 'Natural Oak Finish') because Homebase will be replacing these with cheaper oak veneer seats but the current oak ones share the same product code. Either that or the people who do the descriptions are stupid. Whatever is happening, if you want a warm, natural wooden toilet seat, these are the best and cheapest you will find. Product code is 10022012 if in doubt. Very decent stock in the stores near me and showing as available for home delivery, which will, of course, cost you extra.
The reviews on Homebase are very positive indeed and worth reading if you are in any doubt. 4.6 out of 5 and loads of them (56 in total).