FME, the cabinet wiring of all WPC games like Addams is similar as far as the 'Coin Door Interface' pcb on the l/h side, near the tilt pendulum. The production line would install a pcb to suit the door being fitted - for the u.k, using a C 220 door, this pcb would have more components on-board than for an S 10 door, with up to three mechanical acceptors. The easiest way to have this machine on u.k coinage would be to have that acceptor re-programmed, if it's feasible.
What type of door does the machine have at the moment, btw?. If it's f'r example an original German or Dutch door, you could use some basic S 10 mechanical acceptors for u.k. coins, but I'd expect the wiring would have to be returned to the standard layout, i.e. using a trip-wire micro switch below each acceptor.
Changing the door for a C 220 type isn't difficult (there are four bolts holding its frame to the cabinet), but if doing so it's best to get the matching interface pcb and the door wiring as a complete set. Pinballs have a slightly different sized door to other types of amusement m/c, though. If the opening has been enlarged to fit a different size, that would make this option troublesome.