Today I believe that I saw a mouse running out of the right side of the black boost heater. I suspect there is a mouse hole behind the black unit since there is small space between the black box and the wall but is too narrow for me to check without removing it. I'm now ordering mouse trap to make sure it was not my illusion. Once confirmed, I wonder if I need to call for help, do I have to call different technicians for different tasks? I.e. Calling an electrician to uninstall the heater then calling another expert to maybe fill the hole? What is the common procedure in the UK for handling such problem apart from DIY? Thanks in advance.
If you feel unable to undertake what is a fairly simple job, then I suggest you just get a general handyperson to take Heater off the wall and fill the hole. Mind you, if you have one hole, you probably have more. The little critters do like to get everywhere. In that case, maybe a pest control person is better. Or get a cat!
Cat, had one years ago, totally useless, see a mouse & it hop on on a chair or whatever to escape it. This is a brilliant product, mice & rats were taking it faster than I could rebait the traps,solved the problem. If used outside make sure you create a tunnel on the pests run, say a few bricks, & a slab on top & weighted down to stop othe animals getting to posion. http://www.screwfix.com/p/pest-stop-super-mouse-rat-killer-10-x-40g-10-pack/98146
It may not be a hole, just that the mouse is living behind the heater. Get a trap and see if you catch it, then repeat to see if there are more. The decide if you need to remove the heater.
There is a large amount of space in the bottom of those combo heaters, and I would think the mouse may have just been in the heater, not in your wall.
A few little nipper traps baited with chocolate, bend the bait pin a little so it's harder to pull off, and some poison and your problem will be solved. Vermin like to run around skirting so place your traps there.
Agree on the skirting board tip (with the trigger facing the skirting), but these http://www.screwfix.com/p/pest-stop-sure-set-plastic-mousetraps-2-pack/70203 are better than little nippers. They're less prone to accidental triggering and still crush the living hell out of mice (the spikes are a nice medieval touch). Peanut butter for bait.
If you don't want to kill the mouse, just re home it, get a live catch trap. The ones that are banana shaped and rock when the mouse goes in are best. Catch the mouse and take it for a ride. I was given a piano a couple of years ago, I didn't know it but it has a few occupants, someone else had the gold sovereigns, for me it was mice.