MrDibble, I have always appreciated your international charm, but your mention of ‘mince pies’ just launches you into the stratosphere of international coolness 
{{sigh}}
We had a suet shortage in Piper-land this Christmas, so no home-made Piper mince pies, so no international coolness.
Truly, butterfly wings. 
Oh, giving extra tips to people who come to the house was definitely a thing when I was growing up (binmen, posties, cleaner), but not on boxing day - it’s a bank holiday, so they obviously aren’t working! We’d pay them whichever day they came around before Christmas. I never linked it to Boxing Day, but maybe it was a thing way back when.
In Scotland Boxing Day wasn’t a Bank Holiday until 1974; for many people it was a normal working day.