if you google parceltogo, you can book couriers with them.

£5.99 plus vat with home delivery (says 3days+ but there normally 1-3) but you have to print the labels off

or

6.99 plus vat with DHL (who homedelivery own) and that always gets parcels delivered in 1-2 and you just stick the address on and dont need print any labels.

They both up to 25kgs as well