Yes, a bathroom renovation is a sensible time to add or replace a heated towel rail because walls and pipework are already being opened and finishes are being renewed. The important questions are where it will sit, whether it provides enough useful heat and how the pipework or electrical connection will be routed.
A towel rail should not be chosen only by appearance. In a cold room, a small decorative model may not provide enough heat on its own. If it is connected to the central-heating system, radiator sizing and system balance should also be considered.
Doherty's Glasgow bathroom service includes radiators within the possible fit-out scope, so a towel rail can be planned alongside the plumbing and room layout rather than added after tiling is complete.
