If your whole house breaker trips and not the breaker for the individual circuit it is on, you need an electrician, unless you are running so close to maximum load for your house that any additional load overloads the main breaker, which seems unlikely. Circuit breakers can fail, and if that particular circuit is behind a circuit breaker that is welded closed you have fire danger. You could test it on a different branch circuit.
Since you are in the UK, last I knew code in the UK also required that every mains plug contain a separate fuse. If that fuse is not blowing, you might have a breaker that is tripping too easily. But you still want an electrician to diagnose that. (I’ve personally had to replace two high-current breakers that failed tripping too easily, so I know it can happen.)
But also, if it is tripping breakers, it certainly does seem very likely that you have a fault in the unit. If you are lucky, it’s bad wiring that is easy to fix; if you are less lucky the LPS has a fault and needs to be replaced.
It does sound like you might have multiple problems to fix!