Where to buy a mature plum tree

Hi,

I have a massive plot and room to put a few fruit trees in. I'm not the most patient of people and would like to cheat by putting a more mature tree in so I can see quicker results.  I put in a young cherry last year and it remains a stick, haven't quite pronounced it dead yet but I know I'm just living in false hope!
I was thinking of a plum tree, I still have fond memories of a Victoria plum in my back garden as a child. Any tips on variety and where to get a good healthy well established tree? Having googled it I think I am looking around £25- £35.

Thanks in advance 

RV Rogers of Pickering are our local fruit tree supplier up here.

thanks for pointing me in the right direction, I didn't know you could buy them as big as that Kirsten! I appreciate I will still have a wait but if I can save a few years by paying a bit extra it will help.  I think I'll take a trip out to RV Rogers of Pickering so I can see exactly what I'm getting for my money, thanks for the recommendation Yorkie. I suspect I will be tempted though and my budget will go up!  Thanks to you all for your advice, love this site.

I've made a compromise. Went to a local nursery today and got a two year old plum tree, it's about 5-6 foot tall. Also bought an apple tree that was  in fruit,  (we took them all off for transport, eating them now!)6-7 foot ta. So I will have to wait a few years for the plums but I should get apples next year. Got them for £20 each and I was beginning to think I'd be spending up to £100 for a bigger plum.

It was Wigginton Road Nurseries (road between Shipton by Benningborough and Wigginton). Never been in there before and was just going in to get an idea of what I could get. They were very helpful and when I mentioned I had an allotment he gave me a couple of tomatoes to try that he'd grown, one being an old variety so I'll be keeping the seed if I like it.