Thank you all for your responses.
Karin I know the wool looks fine in the pictures but unfortunately there is nothing intact - you can see the wool has some small holes already above the cuff in that picture but I keep finding bits of wool that have fallen off from I don't know where, I don't know if this is age or moths or something else! I have put it back in a bag as between the 3 materials I can't stop it malting.
I am experienced enough in sewing that I could replace the lining myself with my mother's help, she did a good job on a Harris Tweed Jacket for my father. I tried it on to see what size it is, approximately a UK 6/8 for comfort. (probably too small for me to wear reasonably, I am a 8/10 and I can do it up but the bottom flaps part and I don't think that's a good look!)
The fur is like paper and tears with movement. It would need replacing, particularly as the cuffs are rather small, once on the arms fitted me well, but I struggled to get my fist through!
Mary Jane I adore the colours, my favourite top used both the same shades. If this coat doesn't survive I am definitely thinking of remaking it. My mum said we could take it apart piece by piece and use it as a pattern.
Jonathan I believe the length is original as the lining has the same contrast piped edge all the way around. Thank you for the date.
Can anybody point me to some examples of similar age? I had no idea this would be so rare.