The Payments Council has decided that the cheques system, due to be killed off on 31 October 2018, will now be supported indefinitely for personal cheques. Many guests will still prefer to pay by this method.
For the accommodation provider it is one of the most cumbersome and slow methods: even if your guest's cheque arrives next day by snail mail (Royal Mail) you still have to bank the cheque and then wait 4-6 days for the cheque to be cleared.
The Post Office still provides this service. Better than a cheque from your point of view because you do not have to wait 4-6 days for the cheque to be cleared.
On receiving one of these you should follow the normal procedures for depositing cheques into your bank account which will be credited with the amount of the cheque as with any other negotiable item submitted for clearance.