John Rumm wrote:

2.5A @ 12V DC for about 20 quid by the time you have delivery and vat on
it.

Yup. Or, where I am, 0.00p for any number of well-built, 12V 3A or 5A
cable warts from no-longer-loved laptops. Or indeed the PSUs from old
computers or externally-boxed disk drives, CDs, etc: certainly the ones
from old PCs have hefty 12V rails, though you may find they need a
1A-or-so dummy load on the 5V rail to fire up...

Stefek