I genuinely wish you the best of luck, Guineagirl. even months it took us to get rid of the damned things.
It was horrendous. They were everywhere.
We tried everything. Humane traps, mothballs, plug in sonic deterrents and peppermint oil - trying not to kill them, just get them out of my house.
Then moved on to spring traps, sticky pads and poison bought from DIY stores. We baited traps with chocolate, peanut butter, Mars bars - all of which we were assured mice loved. Well they didn't.
Then we had the council pest control team come round. Made no difference.
I found a 12 hour long segment of rodent deterrent noise on YouTube, which I left running overnight on my Kindle and on my laptop.
Nothing worked.
Eventually we found an independent pest controller, who came in and surveyed the property. He told us where to block/stuff with wire wool and put down some really heavy duty poison.
I wish we'd gone with him from the very beginning. Within two weeks they'd gone. I am still paranoid about them coming back. Absolutely everything in the kitchen is in plastic storage boxes (I found the first one when it jumped out of a box of Weetabix) and not a crumb is allowed on the kitchen worktops lol