Room for one more?

all_hours

You wouldn't have to stop the endowment permanently.

This is a rough calculation - it doesn't take into account the current CC interest.

If you stopped paying the endowment - £300
Cut your food bill by 280
Cut 50 off the rest of your outgoings perhaps £10 off utils, £30 off clothes budget, £10 off haircuts.

This would give you £452 above the minimum payments.
Add this to your current CC payments you would have £1,110 to make the CC minimums and snowball (and still making the 746.25 payments to the loans)
33112.41 of CC could be paid off in around 2 1/2 - 3 years.

Then you could restart the endowment and still have £800 a month to save up for paying off the loans and relax your budget a little if necessary.

How is your credit rating?
Could you apply for 0% or low life of balance cards?
What are the credit limit on your existing cards?

all_hours

One of the first things would be to contact each of your credit card companies and ask them you reduce the interest rate.

Then when you've done that you can decide how to snowball.

The correct way to snowball is pay the minimum on all cards and make overpayments on the highest card.

http://www.whatsthecost.com/snowball.aspx

But, if M&S don't reduce your interest rate, another option pay that off first then when it's clear ask them for the l.o.b deal and also ask them to increase your credit limit. Then transfer what you can off the card with the highest interest rate. What does anyone else think about this - it's a risk because they might not give the deal or credit limit but if they did it would save more.