A mortgage payment holiday is effectively borrowing the 6 months repayments and adding them to the loan. That's good as presumably the rate of interest you're currently paying on the credit card / loan is far higher than the mortgage interest rate. The downside is that by adding these holiday repayments to your mortgage you'll be paying them back with interest for the remaining duration of your mortgage - could be 20 years or more - thus wiping out any short-term savings. My advice would be to do it, but simultaneously to increase your monthly mortgage repayment to counteract this effect.
A payment holiday can be seen on your ICB report but it's noted as an agreed holiday so it doesn't appear as arrears.