Why is it so difficult to buy Cricket kits in the UK?

[WC-Passion]

I've tried buying multiple cricket replica shirts, and finding a domestic team's shirt is extremely difficult. Worcestershire's shop is rubbish for it. So trying to find shirts for teams that aren't in the UK (wanted a Highveld Lions shirt) is quite frankly impossible. Another thing I've noticed is that if you do find the shirt you want, most of the time you can't add any custom numbers or names on the back, or even buy the shirt with the name and number of a current player of the team. Even trying to import shirts hasn't worked. If anyone knows any good websites I'd greatly appreciate it because my experience has been frustrating.