If you want to get a second quote from a specialist repairer, Feet First Resolers, at Foundry Street, Chesterfield are good.
I’d guesstimate they’d quote about 50 quid...which was price I paid when I got some Brashers and Scarpa resoled a way back, but a mate got away with under twenty when he got some Altberg boots re-soled. (Unlike me he took them in when just needed outer sole replaced, rather than complete sole unit.)