so what you recon 2 years experience should be worth?
and which would give me the better career prospects?
For career progression i would start with the MCDST, it will get you out and give you a leg up to a better role quicker than just an ITIL foundation will. If possible try and get both, you never know what your boss will spring for unless you ask

(PS personally i would stay for some time if i got the training, maybe it's just me being a bit old fashioned i don't know, but i always feel that if someone invests some time/money in training you that you should give something back to that organisation/person)
Personally i would be looking at either a Service Desk Analyst around the 16-17k mark, or if you have an amiable personality, good with face to face contact (if you have ever had a bar job/shop job mention it at interviews as these are good examples of dealing with a varied cross section of people!) and don't mind a bit of travel you should look at a desktop support role for around 16-17k also. It all depends on how much drive and ambition you have really. There are people still working at the same company i started at, still doing the same 1st line job for quite low money but they are happy there.
My career path went something l ike:
1st Line (Very ****** busy) Helpdesk - £9.5k to £12k - lasted 1.5yrs
2nd/3rd line Hardware support (Compaq/HP/Dell) - £16k to £18k plus on-call - 1.5 yr
Team/Site Leader for large outsourcing company on a few contracts - £25k to 32k - 3.5 years
Ops Manager - £38k - 2 yrs
Service Management/Business Continuity - £for me to know!

- Currently 1yr
That was all from never working in IT before. So long as you put the work in and have some drive and ambition you can quite easily climb up the ladder in most roles/industries