Just thought i would post my findings, after receiving the four film's back. I was pleased to note the difference in the service offered by the labs,return packaging,documents,freepost box/envelopes for next order from two of the four labs etc.
I found a clear favourite for my own personal use,this was Peak Imaging. I like the return packaging the unmounted slides are sent in,the freepost box is handy also. The most important thing is the processing quailty,of which i find Peak to be so consistent. The slides looked so clean and sharp,with well saturated color. The quick turnaround and resonable total price of £6.19 which was second cheapest,The Darkroom first just by a few pence.
I was pleased to note the quailty of all four labs tested,it is very encouraging to know there are a few good lab's still out there.