Here's something more up-to-date, which seems that they are fine with it, only one or two require the insured to let them know:
www.abi.org.uk/~/media/Files/Documents/Publications/Public/Migrated/Motor/ABI%20guide%20to%20winter%20tyres%20The%20motor%20insurance%20commitment.pdf
Need encouragement in a difficult situation......




and 

