I think you may be hearing the air contractors flight 7001 which leaves STN @ appx 22.00 4 nights a week for CDG
That aircraft is actually the A300 for CDG.
We have an F27 that leaves BHX at 2155 for CDG and returns at 0450 local. Callsign is "1XH" to CDG and "2XH" for the return trip. Both the A300 and the F27 are on the FedEx feeder work into CDG.