Commercial property tenant dispute

[MyRights]

Hi All, I hope this finds you & your family in best of health & spirit. I wondered if anyone can advise or direct me, I own a commercial property and have had it rented out on a commercial lease agreement since 2015 to the same person. At the time, I advised the tenant that as we are doing this as a short term lease there will be an increase in rent in 2016, he agreed and signed. Come 2016, he said he could not afford to increase the rent but agreed that we will put this in writing in the agreement that it will go up in 2017 with the agreed the amount from 1200 to 1350. Come 2017 he continued to pay the same amount (1200), I followed this up several times, and he eventually increased it to 1250, then in 2018 to he increased it to 1300 and only recently in 2020 to 1350, none of this I agreed was a way for him to pay. Of course in between, I have been chasing him to meet with me to find a solution that works for us both. To avoid ending ending the contract and potentially have the property empty. It's taken this long, as I was considering his circumstances (severe illness's, wife's cancer diagnosis etc). However, when I last spoke to him (26/03/20) and urged him to restore his integrity and pay the new amount £1450 so I can recuperate the money he owes, he refused that he agreed to the increase in the first place. I told him to refer to agreement and was meant to follow up with a formal notice to clear the balance or leave. However, Covid happened and in this time he asked for a rent break but is fully functioning (more than before) as he is an approved NHS supplier (and has received the government business rate grant). In total he is in debt to me by £2200, I was initially thinking to send him a written notice to clear the balance in 10 days or leave in 15 days after that (agreement clause is that if any clause is broken I can give him 15 days notice). But I wanted to make sure this is the best way forward. Please help