Only two aircraft I could find with an "F7" designation that had Rolls-Royce engines were the Vickers F.7/41
, WWII-era single seat fighter, with a similar appearance to the Mosquito, and the Supermarine Swift F7
, a 1950s-era jet fighter prototype.
Of course, there is also the USN
F7U Cutlass and the Chinese-built F7, a version of the MiG-21, but neither used RR