Raw steel frame care/rustproofing

Don't waste time with clearcoat, it's poreous and water will get in. Pour some engine oil on a rag and apply generously to the frame. Ideally should be left in the sun afterwards, but left in front of a heat lamp for half a day or so would be fine too, this allows the oil to leach into the pores of the metal and actually give decent protection. Wipe the excess and repeat the process and you should be good to go. In England rust is more or less inevitable, it's pretty much not if but when. This is pretty much your best bet.

I got some diesel engine oil from Halfords and rubbed it all over the frame with a rag. Going to leave it inbetween 2 radiators and do a second coat in the morning.

I also bought some Waxoyl to apply to the inside, but after reading some less-than-positive comments regarding it interfering with other components and leaking out of the frame, I think I'll give it a miss.