This might be of help. I have seen kaleidoscopes in a mail order magazine called "Past Times", they also sell things like old fashioned toys, jigsaws, old style money boxes where a dog eats a coin, etc. It might be worth googling for Past Times. I hope you are successful.
I know you say 'UK' but... one of my favourite possessions is a hand-crafted kaleidoscope I bought in Key West in the US many years ago. It's burwood and brass, with the 'bits' suspended in a special oil. Everyone who holds it and tries it falls in love with it! It was quite expensive but worth every cent. The maker is Randy Knapp who still specialises in kaleidoscopes - his website is www.knappstudios.com. I've written to him since - very friendly man, who would supply overseas, I'm sure.