Good, fun mountain bike/downhill routes in the Newcastle-Gateshead-Prudoe areas?

Just when I thought buying a helmet was the one last thing I'd need to do, my bike arrives and there's a lovely dent on the frame. It will need to be refunded, replaced, or exchanged for a whole new bike now but the returns team aren't gonna be open until tomorrow morning now

Anyone know what the deal is with replacing frames? What things need to match up in order for all the parts to be fully interchangeable? I'd much rather have the frame switched and keep the rest, but I have a feeling they won't be able to find me anything.. at least not as good.