Note that some banks hard search on opening and that’s reporting to 1, 2 or all 3 CRAs that you have a new bank account.
This temporary affects credit scores (which are meaningless) but could impact in lenders decisions based on the overall age of active accounts.
I haven’t found it’s done anything in getting the mortgage I wanted but it’s impossible to know if it was affected and in any way as every lender has its own calculations and age of account might be used, might not and if it is have different weighting compared to other factors.
As for scores which again are meaningless, Experian and Credit Karma doesn’t care about hard searches on your TransUnion report so no impact. ClearScore minuses 34 points for the year from the hard search date based on Equifax, and adds 34 back after that.
It’s all nonsense though designed to trick people into buying services to improve their own scoring of you.
Especially if you’re not needing loans/mortgages then hoovering up cash seems a no brainer to me. So easy doing Cass too compared to the old days.
This is a good place to monitor, the amounts usually vary during the year. You can’t keep doing the same switch each year unfortunately so you’ll need to note when you last applied to a specific bank.