Indemnity and missing covenant

caleo

I bought my house in 2000 and am in the process of selling it. The buyers solicitor is asking us to pay for an indemnity policy for a missing covenant - the land registry states

"a conveyance dated xxxx between xxx and xxxx contains restrictive covenants but neither the original deed nor a certified copy or examined extract thereof was produced on first registration" the conveyance date is from 50 years ago, relating to the builders of the property.

I am chasing up my old solicitor to see if an indemnity policy was in place when I bought the house, but it seems that the only indemnit policy they have is the one I paid for pertaining to my house that I was selling at the time.

Were the solicitors negligent in not ensuring that I was covered by an indemnity policy - or is my buyers solicitor being extra cautious?

Does anyone know If a policy had been taken out previously would that cover everything now, or would a new policy have to be purchased anyway?

Thanks