The problem I suspect is not the wiring age, it is the thatched roof.
No electrical election need be brought up to date, an insurer may request a n electrical safety certificate - which is not the same thing. That will hi ghlight any specific fire risks - for example butyl rubber cable hidden fro m view re PVC crimped onto PVC tails, broken wiring accessories, incorrect MEB, missing earth re supplier or earth rod with non-functioning RCD (!), y ou get the picture?
For a thatched roof I strongly suspect most insurers will tell you where to go, simply because their dumb databases will list high value property + fi re/electrical + sodding great big total loss.
If you were re-thatching, Class-0 fire (Silica/Glass) overlapping board may either be required or an extremely good idea.
A broken rewirable fusebox, ceramic DNO cutout, earth rod out of spec with corroded away cable, faulty RCD so certain faults simply sit there setting fire to your thatch - they are the risks with thatched. Never mind chimney risks which require proper guards or ideally no open fire at all.
There is BS8436 cable which has a foil shield capable of providing Type-B L
-N fault disconnect without RCD when penetrated by some definition of nail. For a thatch this could be good when combined with RCD, altho to be honest it may be quite unnecessary - unless thatched also includes mice visiting from the nearby field in which case you are going to need SWA re teeth :-)