AIBU neighbours in house?

[2bamum]

Quick name change!
AIBU
New neighbours moving in they want access to our house one weekday 3 weeks before Christmas because thay want to have work done and it involves checking it from our side!
The work is entirely optional (they are installing something and will not be without heating/hot water etc)

Thing is we both work full time neither of us wants to take a day off to wait in for their workman, and the days we do have off we have plans for (family birthday and Christmas shopping)
So WWYD?
AIBU if I say it doesn't really suit and if pushed give them date in the New Year?

Wow... I'd never give keys to strangers, neighbors or not.. Maybe I'm unreasonably cautious, but I just wouldn't chance it. What if they left the door unlocked on their way out and someone else got in?

This may be totally thick of me but...if they were going to require access to your house, shouldn't they have asked the OP before making the appointment? Come on, who gets given days off just before Christmas?