Yellow flower

We have a shrub in the garden which I planted some years ago.
However, we just can’t remember what it is but think maybe St. John’s Wort?
Of course this is one of it’s flowers hence me blipping it because I know, out there in blipland, there will be someone who knows what the shrub is.
It’s a bushy shrub and quite dense and I fear we haven’t been pruning it as we should because it taking over one corner of the garden. Help......