Details? Would these all be BA flights?

1. It's not wise to have a LHR-Spain and LHR-CDG flight booked on the same carrier (or even close partners) for approximately the same time. You risk cancellation of one or both flights, although the risk depends on how good the airline is at detecting double bookings.

2. If you skip LHR-Spain, the remainder of your ticket (RT award ticket?) will be cancelled.