Good to hear you have hedgehogs back there. There is a certain amount of variability of when they return. Some choose not to hibernate at all.
If you keep watching the hedgehogs you will find that the youngsters, in particular, often mount females, but for actual mating to take place is a bit more complicated and the female has to co-operate. It usually follows a quite lengthy ‘courtship’ where the male circles the female – she also turns round and round within the male’s ‘circle’ (huffing as she goes) so that her face is, pretty much, towards the face of the male. This can go on for hours and is very often what people are hearing when they hear the sounds of hedgehogs. Very often after these lengthy circuitings the two will part without ever having got round to actual mating.
It’s possible that the earlier ones back from hibernation are males and/or youngsters. The mature females tend to return a little later, having gone into hibernation later (usually due to hoglet rearing duties).
Hopefully, they will eventually produce some hoglets.
Good luck with them all.