outstanding debt for rent arrears

Rent Arrears

Hi, I have a rented property and the couple now owe us £3,200 which they have done since the Coronavirus pandemic caused them to stop paying their rent altogether for a period of time. No communication was made from them to say they were not able to pay or as to why they were not paying until I contacted them.
I gave them space and kept them informed of the mounting debt and did not pressure them about the rent, when the pandemic restrictions ended they started to pay their rent again but made no attempt to pay down the debt or to make any contact to explain.
I have now asked twice for a payment plan via text or whatsapp message but they only reply if I message them several times.
Last time I suggested £50 a week payment to reduce the outstanding amount but was told the most they could afford was £50 a month, I explained that would take an exceptionally long time to pay off and was insufficient to make a real difference, however no additional payments have been made since to pay down the debt. The husband then phoned me and said you may as well put us in court as we have nothing as his business was not operating any more, I asked if he was working elsewhere to which he had no answer other than what am I supposed to do with my business? I suggested it may take a lifestyle change as we have all had difficult times lately.
I have asked to have the house Valued by a local estate agent as I am having my portfolio appraised but in 2 months they have not responded to any of the agents calls and last time I asked, the lady called and said she would arrange it during her tea break next day, that was 3 weeks ago and nothing has been arranged to date.
I am now so fed up I want to take possession and make a claim in the small claims court, however all my correspondence has been by message or text other than the coronavirus paperwork and guidance letters I sent and no debt letters were sent due to the Coronavirus restrictions on debts and evictions.
Having looked through the NRLA guidance the rent arrears templates do not suit my situation to write to the tenants prior to the small claim application and the issuing of the section 21 as it is now an outstanding debt and not just late rent payment.
I now feel this is my best option as the debt is so high and the rental value for the property is £250 a month more than the current rent.
Could you please advise?