Hi Daisy,
Most that post here are in the USA. We also have some in the UK, Netherlands, but not a lot. Hopefully someone will jump in.
If you can - find a club and ride with them. If you plan to race that means riding with others. Search for clubs, look at local coffee places on Saturday and Sunday AM and see if the cyclist are starting. Also see if you can find races. Maybe you can go there and look. Internet search UK cycling events etc.
Yes - there are good helmets under 60GBP - even with shipping. Always look at shipping.
These are a good, off brand.
EKOI CORSA EVO White / Red helmet