Carson,
Carausius et Fratres Sui, no. 9, reports a coin like yours, but in
obv. legend AV for
AVR and P F for P, "Photo in BM,
RIC 337".
Same
obv. legend as last,
rev. PROVID
AVGGG, no. 40, "
Oxford,
RIC 365".
Same
obv. legend but
AVR like yours,
still however P F not P only, no. 56,
VIRTVS AVGGG, "
Oxford,
RIC 443".
These are the only reported coins in the S--P / C issue that give
Carausius that second M for Mauseus.
Maybe you should consider trading it to another
Forum participant, whose code name seems to indicate he might be interested in it!
Sounds like
Oxford too might be interested, if they want to corner the market!