UK Cash Deposits

I’m in the process of selling a car privately. I suspect the payment may be made as cash (not ideal I know). Apparently the post office take payments up to a max of £1000 per month but no more than £300 at a time.

My wife and I both have personal Monzo accounts and we have a joint account.

Will we be able to pay £300 in to each account up to £1000 per account? £900 per visit equaling £2700 for the month? Split across the 3 accounts.