We currently have limited customer service staffing due to Coronavirus (COVID-19) safety precautions. We encourage you to find quick answers to your questions by searching the community forum, visiting our Help Center, or messaging us (message response times will be delayed). Thank you for your patience.
There is no automatic way to downgrade a business account to a personal account, you have to contact customer services and they will do that for you.
Click help / contact bottom left of Paypal pages for options available for your country.
Or have you considered contacting Customer Service via Facebook or Twitter? You can send them a personal message from their facebook or twitter pages. It's: https://www.facebook.com/PayPalUK and @AskPayPal for Twitter. OR You could just close your business account (removing all subscriptions / financial info etc first) and open a personal one.
Advice is voluntary. Kudos / Solution appreciated.