Hi Wifflesnap and a warm welcome to you from all the Staff and Moderators.
All things Scottish can be found
here. Also, keep an eye on threads titled something like Scottish Bashes; we try to meet up occasionally and they're always great fun. You'd be most welcome to join us on another if you can manage.
As for Long-tailed Tits... you
will come across some and may even get them in your garden if you're near to some woodlands, but in the meantime maybe your best bet would be to get into some suitable woods or forests (even riparian woods will do) and listen for them. You can hear their song in The Opus article
here (scroll to the bottom of the page or click on Vocalisation in the Contents Box). At this time of year, they often travel in bird waves with other species, such as the other tits (Blue and Great) and Eurasian Treecreepers; you can read up on them in The Opus too.
Sorry, I don't live local enough to know of any local populations. But if you post in
this thread, someone more local to you may see it when they've sobered up
A merry Christmas and happy New Year to you and your family.