Yes your garden centre will stock ericaceous compost and this is what you need.

Thanks for the reply, I have them both in ericaceous compost but I'm concerned that if I feed them with the wrong fertiliser I may not give them the best care.
Do blueberries need a fertiliser with a different ratio of nutrients?
Thank you.

Sorry should have said your GC will stock ericaceous fertiliser - though I'm not sure blueberries need.

That's what we recommend here in the desert, though they need far more feeding here, than in MG's area.

Most water in your area is soft - if your kettle does not have any furry deposit in it you can safely use tap water - otherwise, yes, rain is the thing.

Thanks folks, much obliged. I'm on my way to B&Q today to get some.
Thanks for the tip about tap water Steragram, I didn't know that.

If you want to go organic Hoof and Horn is the traditional slow release fertiliser for ericaceous plants.

Buddlejagar

What on earth is Hoof and Horn??

A natural fertiliser:

http://www.angus-horticulture.co.uk/online-shop/traditional-fertiliser/traditional-fertilisers/hoof-horn