There's a similar irony in the new car tax (VED) system. You pay for your car tax online, and you no longer have to display a tax disc. +10 for belated arrival in the 21st century. But if you sell your car you have to apply for a refund of the remaining tax, which is sent as a cheque in the post. -10 for lack of follow-through.
I suspect that the offices of HMRC and DVLA are still like offices used to be half a century ago. For anything to do with paying out money you have to go to a cashier's office where a grumpy old geezer behind a barred window grudgingly writes out cheques using a dip pen.
("CHEQUE PAID IN A BOOTLE PAYMENT OPS" - I bet the cheque would clear quicker if it wasn't in a bottle.)