Swimming for reluctant 4 year old

[SlowDown]

I'm planning on booking some swimming lessons for my 4yr old in Sept, very nice sounding instructors who can cope with reluctant children apparently! Leading up to it want to start taking him swimming myself to get him used to being in the pool. We've only been swimming a couple of times since he did a course of lessons when he was 2 and he's reluctant at all things swimming now! Anyone got any advice on what I should do during the sessions when I take him? When he was 2 I used to support him myself and pull him along in the water (amongst other things) but is that still good for a 4 year old? Or should I try to encourage more independence from me with arm bands? Sorry, I'm clueless despite being quite a confident swimmer myself! Would a swimming noodle be a good idea? Just want to get over this reluctance so he can start to learn but as he's so tricky when starting anything new I predict it's not going to be easy!!
Thanks

Hooray, we went swimming today at the leisure centre where there's a learner pool (nice and warm)and we were there about an hour! Started off with me in the pool and him fearful on the side and I passed him floaty things and he pushed them back to me. Then gradually got him to go down a step to get the floaty things. Took it really slow, no pressure and by the end he was in the water pushing around a frog float! Amazing, we were both on a high. It helped that it was a family session with lots of floats and things in the water and it wasn't very busy. And I was mega patient this time and everytime he so much put a finger in the water I was over the top on the praise!! Hope it carries on as well. Thanks everyone!

PS, the weird thing was that after 2 visits in the last week just to look at the pool, today he was actually asking to go swimming!