It’s hard to be sure from short descriptions on the forum, but it does sound a bit like male hog behaviour when there are females around – especially the more dominant males – when they will often tear round the garden seemingly ignoring everything. I always think of it as ‘being on patrol’. But they do tend to look a bit ‘hyper-active’ in those situations.
Once the hogs have come out of hibernation they won’t necessarily go back into that box again (or in your case its replacement). If Harry has stayed that long in the same box before, that might have been unusual. Hogs will sometimes even change nests during hibernation time, not least to avoid build up of parasites.
Normally the male hogs would come out of hibernation earlier than the females (having gone into hibernaton earlier). That gives them the chance to put on a bit of condition before they got involved in wasting a lot of energy circling females and biffing males (as well as tearing around searching for other hogs). But there may be some females around already. Some ‘rescues’ tend to release over-wintered, previously underweight, hoglets once hogs start emerging from hibernation and the weather is nice. But there could also be some females who chose not to hibernate. If non-hibernating hogs have access to sufficient food, even the youngsters will put on weight over winter.
These are amongst the ways we humans could be inadvertently impacting on hog behaviour. i.e. females normally hibernate later than the males and then emerge from hibernation later. Any female hoglets from the last year which may emerge earlier don’t normally seem to be particularly interesting to the males until later. Although if they have put on weight and size over winter, that might be a different situation.
But it’s possible that Harry has become more dominant (or wants to be) and is patrolling his range more energetically. Alternatively he was already the dominant one and wants to keep it that way!
Having said all that, if you are, at any time, worried about a hog you can ring the number (bottom left of this page re. sick or injured hogs). They will be able to give you the number of your nearest hog carers, but you will also be able to explain the behaviour more fully than is possible on the forum.
Good luck and happy hog watching!