If you have outstanding disputes with your bank, that you have complained about and are still unresolved, his might be worth a look. The Business Banking Resolution service claims to be a good fit for SMEs.
They will take on cases going back to 2001 which is good, and have the power to order the banks to pay up.
For more information see https://thebbrs.org/contact-us/
0345 646 8825. lines are open Monday-Friday between 9 am and 5 pm.