Tell your friend not to do what I did and hire an eMTB for the day from Alpine Bikes at Glentress. Too many £££s later...
Seriously though, EAPCs can be very addictive. Your brain says you're cheating, but you still have to put effort in to make the thing move, and once it's moving you don't want it to stop so...you keep pedalling. That's one of the main differences I find: on a normal bike I'd stop for a breather every so often. An ebike just seems to egg you on. You might use fewer calories overall, but the workout is arguably more intense (unless you really are the sort of person who actually enjoys suffering - I'm not).
To answer the actual question: I believe Halfords used to offer demos of their ebikes but they seem to have given up since I last looked. Maybe they've become so easy to sell that they don't feel they need to any more?
As Gembo says, Harts are probably one of the better bets for a try-out in this locale.