Ambassador, British Airways; FlyerTalk Posting Legend
Join Date: Apr 2012
Location: Leeds, UK
Programs: BA GGL/CCR, GfL, HH Diamond
Posts: 42,997
Nope. You are fine to hold two bookings for the same flight, BA won't search and auto cancel one.
You plan sounds fine. Obviously the cancellation of the one you don't want will be subject to the usual cancellation fee of £35pp.