Bank account probs during mortgage app

Bouncybubbles

Hi
As some of you will have seen we had mortgage offer in full no probs etc, however due to a spelling error it's had to go back to underwriters which is where we are currently. Now due to having a few biggish expenditures this month inc solicitors, vet bill car birthday etc it's left my bank account a tad short for the bills. Now all our docs are with santander so doubt we will have to send anymore as app already approved once etc. So my problem now lies with so I transfer £200 from a cleared credit card £1500 limit balance £0 to top up my account, or do I leave it with the possibility of missing a couple of bill payments? The £200 will be repaid within a week as awaiting a refund from a cancelled festival. But if I use the CC will it show up and be detrimental to the app if it's credit scored again?
Btw the CC was declared at time of app so it is known about but obv the balance would change if I were to use it
Thankyou all

Bouncybubbles

Also I know it looks like I'm an irresponsible borrower but our mortgage will be £80 less a month than we pay for our current mortgage and it's been a dreadful month for money we normally wouldn't have to find