I can't pretend to understand any of it, but as far as I can see, if you're serious about distribution/airplay/receiving performance royalties for your album, then you need to register with PRS (performing rights society). And they will sort out your covers for you.

If you're not that fussed about PRS, and only realistically expect to be flogging the CD via your own two hands at gigs, then personally I wouldn't bother registering.

Are you a member of Musicians Union? If so, I'd ask them - that's the sort of thing you pay union membership for.

Either way, I think your instinct is correct - I can't see why you'd have to involve Harry Fox.