I have just fitted Oxford Heated grips. Not a difficult fit, £55 from Argos. Chuffed with the results... Rode in to work with my summer gloves the last 2 days on 75%. Long motorway run with my winter gloves (aldi jobs) was also fine.
Heated gloves look like more expense and faff to plug in every time.... Also I happen to rather like riding in summer race type gloves
, and can see them being nice year round when the sun dissapears.