Okay, I have no idea what happened there. When I searched for 'dsm2 compatible receiver' last night, I got tonnes of options with loads of them being around the £5 mark. That was the link I posted. But for some reason, it's now only showing six options around the £25 mark

And I think I just used an external failsafe between the battle-switch and the receiver. It's been a while since I had that setup, struggling to remember correctly!