I always recommend people have their personal and business accounts with separate banks and generally say nothing more when it comes to small businesses and banking facilities.
I now have one more thing to add:
If you get rid of a business (sell, close, wind up etc) and it has bank guarantee on you, make sure you specifically cancel it, getting written confirmation accordingly.
Someone I have been working with had a business, closed it (without debt) along with the bank account (it had an overdraft, which was guaranteed). A few years later, he opened a new business, with an account at the same bank. They had a few troubles and the business closed with minimal debts/overdraft.
The bank invoked the PG.
What people forget is that a PG is exactly that - personal. Whilst it may be taken out for business reasons e.g. overdraft, loan etc, the bank will use take any opportunity to call it in!
Sadly, after speaking to a few people who have sold or closed their businesses, of those that had PG's, none had taken an action to cancel it!
Make sure you are not caught out and cancel any old PG's that you may have!