It's a few years since I worked for real and I don't have the references (or time) to hand to check.
But as I recall it depends broadly on your flight 'rules' for arrivals. If you are VFR or making a visual approach you will be given the recommended minimum spacing from the aircraft in front. It's up to you to arrange the spacing that you want. If 'full' IFR, ATC will give instructions to assure the minimum spacing exists. Some airports seem to have procedures which permit the spacing to be eroded inside 4 NM from touchdown but I don't think this is part of the national rules.
For departures the minimum spacings for take-offs apply to all aircraft irrespective of anything.
Of course, as you fly a helicopter things get more complicated. As I recall, if you are using the runway you get the same spacings as fixed wing aircraft. If you are using grass alongside the runway you get treated like you were using the runway (I can't remember whether this was just at the airport I last worked at or in the national rules) and if you were using another part of the airport we just take lots of care and exercise individual judgement.
At airports with lots of heli ops - especially big ones - you'll probably find local procedures are developed for common operations. The national rules are in the Manual of Air Traffic Services Part 1 (CAP493) available on the CAA website.
I think this is all roughly right but hopefully someone current will be along before your CP's meeting to either confirm or correct the above.