£25 for a new wheel sounds good enough.
You probably will hae to take the old wheel the the shop anyway. They will probably reuse the freewheel, tire, and tube (assuming they are all good).
Even if you were to rebuild the existing wheel, you would have to at least pay £5 for a replacement axle and cones, and another £5 for new bearings. Even without labor, pretty quickly you get up to the cost of a new wheel.
BTW, if I have a fault on the road, I will evaluate whether it is safe to ride the bike home. In your case, I probably would have walked the bike home rather than risk irreparable damage to the components.
Once you strip the good parts, consider donating the remainder to a local bike Co-op. Someone may want to rebuild it.