Tenant has failed to vacate after expiry of possession order

Possession - Section 8 and Section 21

Mandatory possession order ground 8
Owed we £3500 in rent.
Has sent an email saying unfortunately unable to vacate but aim to communicate on exact move out date in coming days. I am keen to get him out asap as he has been a nightmare over last 7 months. accountant now a shop assistant, living beyond his means.He will try everything possible to delay eviction
Can a warrant of possession of land be done on line via PCOL?
What are the fees
How long does it take?

The court bailiffs via MCOL have been totally useless in the past for another debt on the same tenant-visited the property thrice during daylight hours, no answer on the door, end of the story!
Thank you for advice in advance