Ambassador, British Airways; FlyerTalk Posting Legend
Join Date: Apr 2012
Location: Leeds, UK
Programs: BA GGL/CCR, GfL, HH Diamond
Posts: 42,990
you do have to call to cancel if it is a voluntary cancellation.
a £35 per person cancellation fee will be deducted from the taxes/fees/charges you paid - if you paid less than £35 per person you are not asked to cure the difference.
you can get a FTV if you want and use that towards a new reward booking in the future, all the avios and cash will just be held on the FTV for use by april 2022.