I have the estate agents hounding me although I think they should have told me this prior to me making an offer.
I wouldn’t worry about the estate agents. Your offer is not binding. tell them to do one.
Very hesitant to proceed now given this has come to light, mainly because I worry I won’t be able to sell in future…
if it’s a worry to you, then it will probably be a worry for anyone who may looking to buy when you are selling.
Legally I have no idea where you stand, although as long as you have hundreds of years on the lease, I think you would be fine even if the freeholder turned up. Have you spoke with a property lawyer?
If it was me, I would either walk away or reduce my offer to reflect what I thought this matter affected the value.
Would you have made an offer if you had been aware of this before hand?
A house is only worth what someone is willing to pay.