Hi Ciggy, I'm also in the UK, the only site I've found with 25's is this one but they are silver printable plextor branded TY.
There is also some white printable 8x at jetcase.co.uk. But these are quite pricey.
As TY is only shipped in cakeboxes of 100, it's up to the seller whether they want to repackage them into 25's.
Hope this helps