if the glass has come away then the only proper repair is a new top, look up the cost and then say its also damaged at least one of the pcbs, the cost of those will put them off repair. I had one of these (customer reported the glass being “springy” from new- thought is was supposed to be floating like that!) her final bill came to £2500 and a lot of stress for me. (and no profit given the amount of visits and time spent on it) (wasn’t a 100 though but a Falcon branded 110 in my case)
Water gets onto the potentiometer there is a mod for it I think but you would need to get hold of rangemaster technical these are easy to work on 2 screws at the side and the top lifts off