Banks have to fill out massive amounts of paperwork online if you start moving large sums between accounts. Last week, I had a call from our joint account questioning a payment (to a company putting in mains water and drainage for us) and when I transferred the money to cover it from our savings account with a second bank, it had to be paid by bank cheque and logged for the prevention of fraud.
For sure, all that activity will be scrutinised against our business and personal accounts, and again by HMRC. Legitimate earnings and savings, all taxes duly paid, but according to the branch manager over 50% of all the work done in bank branches originates from fraud and scams.