What to Wear?

As someone that normally steers well clear of cold water, I don't have a handy wetsuit in the wardrobe, so what to wear for the Triathlon swim?
Everything I have read says that you need a special swimming wetsuit that will keep you warm, but is flexible enough to swim, and also has a smooth surface to reduce friction.
But these are quite expensive for what is probably going to be a one-off event for me.   I could hire one, but then realised that Amazon has a mega special offer on a 'normal' one that makes it about half the price of hiring a good one.
So I have bought a very cheap 'normal' wetsuit (for <£19!) to see what that is like - if it proves impossible to swim in, I will hire a good one.

The wetsuit arrived this morning and I was pleasantly surprised - I managed to put it on, and I can imagine swimming in it - I think the limiting thing for the swim will be my poor technique rather than poor equipment!   Even tested it by getting into a bath of cold water.  I can't say that it was pleasant, but I could lie in it without feeling like I was getting hypothermia.

Will try it out in Hartlepool Bay on Saturday morning......