Having ran out of time at the weekend to fully soak test the C64 PC, I’d taken it in to work with me and left it switched on were I can keep an eye on it.
Temperature wise, it rose from around 16c to about 55c during the course of about three hours.
Although 55c isn’t that hot, to appease any concerns I had, I fitted a quiet case fan at lunchtime to to see if that would help. It seems to have done the trick as the tempreature rose much slowly and peaked at around 40c throughout the day. Again I used the adhesive velcro pads to secure the fan in place.
Whilst I had my soldering iron and tool kit to hand, I drilled through the C64 case and fitted the replacement PC on/off switch. It’s a much better switch I was previously using and is conveniently placed on the side of the case instead of the rear.