Historic value of land for CGT purposes

[MrsJervis]

DH inherited a parcel of agricultural land from his father several decades ago. Last year, we sold the land, and we now need to work out our CGT liability. Only problem is that we don't know how to work out the probate value of the land. The only sum we can find in documentation is the total probate value of late-FIL's entire estate (of which DH's land was just a very small part). We've contacted the firm of accountants who handled FIL's affairs at the time and who still look after the family farm but they can't find any relevant documentation. Does anyone know whether HMRC would accept an estimate from a local land agent? Or is there any other way of getting this information? All help very much appreciated. (Am also going to post this in Legal in case anyone there has an idea.)

There normally has to be a set of accounts done for probate, and sent to beneficiaries (although may be different if you get a specific piece of land) - can you find out if those accounts were ever done? Surely the accountants should hold records for so many years, esp when doing probate? Was the land listed specifically on the probate application, did you or can you still get a copy?

Other than that, no idea but hopefully someone who does will reply?