Could someone run some numbers for me please?

Snooze2

I'm needing £3k to tide me over for around 6 months.  I rattled in a loan app through my bank Santander and got approved but they've hiked the APR up to 24.9% as apparently they consider me to suddenly be a high risk.  The total repayment is £3372 something based on £281 and some pence per month.  That's in credit card territory, but needs must.

I've got a Virginmoney CC and they're showing me a cash transfer offer of "0% interest until your statement date on or after 07/03/2021 with a 4.00% fee then returning to your standard interest rate. Offer available until 07/05/2020."

I've no idea how CC interest and fees are calculated.  If I were to take £3k through them and pay £250 per month over 12 months can anyone tell me how much I'm going to get rushed for?  Is it as simple as £3k + 4% = £3120 total or is it more complicated than that?

Thanks all. 

Duckyduck

Provided to clear the balance by 7/3/21 then yes, total core payments will be £3120.