Think I’ve already got the answer but got some new wheels for the missuseses bike and was thinking about using the old ones for mud plugging duties. Google fu says no but wondered if anyone on here had bodged some hope adaptors or similar?

It’s not just a matter of finding an adapter, it’s whether the hub is physically big enough to accommodate a 15mm axle *and* a bearing around it.

Almost certainly “no”.

The ID on the current bearings is 15mm….so with a narrower bearing….possibly… but doubtful