Thanks for the info Andy.
Regards to the Zenith carb i basically had to make one good one out of all the carbs i brought as all had “issues” with them.I still have one left which is “NOS” (new old stock) but someone has allready tried to remove the brass main jet with a poor fitting screwdriver and mangled the slot up.I know you can buy brand new Zenith 24T-2 carbs (from that auction site) but they are expensive.They were fitted on many different engines and tractors etc including Ferguson TE20 and TED20 petrol and paraffin tractors.Personally i would try to buy a cheap used carb from that auction site and make a good one up as i did.
Several years ago Andy i brought a new 24T-2 centre gasket from Meetons (the Villiers and other small engine spares specialists) so they may have other Zenith parts available too.May be worth a phone call if you only need a needle and seat to repair yours ??