you have to be a sole trader to qualify ?
It works for that. Or hang on to the account in hope that one day there will be a business banking switch offer from another bank etc. And you can try and persuade people to use your 50+50 referral once you've got the account (sadly, no one I know is willing to give that a go!)
How about grab £50 and move on
Avoid them if possible. Yes it's convenient and a new way of banking. However if you have a problem, be expected to wait an eternity for a resolution and receive generic responses! You can't pick up the phone and speak to them. And as a small business owner when I have fraud or transactions are being blocked I need the issue resolved ASAP!
I recently moved to Mettle which I would recommend as they include FreeAgent access, which is worth £19-£29 a month depending on whether you're a sole trader or a Limited Company.