For spray application you really need to buy from a specialist.
Try Morrells
[URL unfurl="true"]https://www.morrells.co.uk/[/URL]
or Movac
[URL unfurl="true"]https://www.movac.co.uk/wood-finishes/interior-wood/[/URL]
basically you have these choices:
1) waterborne, they are solvent free, easy clean up, but they are tricky to spray, dry slowly and raise grain.
clear lacquer is great as it stays white and doesn’t yellow pale timbers
2) pre cats: a good product to start out, solvent based, quite easy to spray, dries quickly.
3) acid catalysed: a 2 pack, dries very hard, resistant to scratching. Contains some nasties, wear the proper mask
4) PU: the best paint for spraying really, very thin coats can be sprayed, dries very quickly, finish is very tough.
however it contains isocynates, so you need an air fed mask and proper extraction system
generally waterbourne, pre cat and AC are sprayed with a 1.6 to 1.8 tip on an HVLP gun
PU is sprayed with a 1.4 tip
You can buy morrells from eBay - a 5 litre pre cat clear is about £40 or so quid
AC is likely to be £75 for 5 litres incl catalyst.
