Any plumbers about?

[Frustratedandworried]

I know, I know, I should of hired a professional

Redoing our bathroom ourselves and it's going fairly smoothly but we have hit a few hiccups that may require a plumber however money is extremely tight we have none so I wanted to ask before we continue:

1. bought a brand new click clack slotted waste trap... it wont click shut when I've tested it before installing... is this normal?

2. is replacing a radiator with a radiator heater a DIY job if the radiator is the same size? Sadly no isolated on the radiator which makes me think not?

I feel very silly for attempting this solo but needs must at times.

Any advice that can be given will be greatly appreciated even if it is " stop eating for a week and hire a plumber"

What's a radiator heater?
Assuming similar then yes the main thing is draining the water from the system which would be at a drain point low down, then undo the old radiator and plumb in the new one and fix to the wall. Then refill with water plus inhibitor and check for leaks. Loads of videos online.

Ps everyone feels silly the first time, if there's a second time then you'll be the expert by then!

Sorry I meant a towel heater! I know they dont have great heat output but due to the location of the radiator / toilet and small kids we dont ever have it on anyway! Thank you