A quick way to know its all hot enough is to apply the solder to the opposite side of the pipe from where you were heating.
Yup good plan - I tend not to fit many clips before I have soldered it up, but sometimes you need one or two.
Can't say I was that keen myself either, but she was in hospital following a fall, and needed to come home to a place with a easy access shower, rather than a cramped 1930's bathroom. So I was going to get lumbered one way or another - so it was easiest to co-opt a retired builder I know to go do it with me, than trying to organise others to do it.
Its surprising how annoying even computers can be when you have just wiggled into the right space through a hole in the the floor, and someone else rings to ask you what their email password is ;-)