Aside from that, I will be buying an electric shower (not sure if
Homebase will install that as part of it or not) so any
recommendations on that would be welcome and also how much I should
expect to pay to have it fitted.

I would only install an electric shower if your house does not have a hot
water system, or it would be too difficult to plumb hot water supplies to
the room.

What sort of hot water system do you have? Perhaps we could recommend an
alternative.

Christian.