Any help appreciated with this. I was swapping my manual cam chain tensioners from the old Storm to the new one and accidentally dropped a small bolt into the rear engine casing

It was on the cam chain side (RH), and its the central bolt that holds the cam chain guard in place. M6 I think and about 10mm/15mm long.
I fished about with a magnet but no joy so what im wondering is.... If I remove the sump or clutch cover do you think the bolt may be retrievable or will I have to strip down the entire engine? When it fell it clinked a couple of times then a muted clink like it had hit metal under oil so it may be in the sump perhaps? Iv never stripped a Storm engine down so not sure if it could fall all the way down or would it get trapped elsewhere.
Regards
Phil