I have processed both E6 and C41 in Fotospeed chemistry and provided the temperature control is good I would say you will have no problems. I would prefer to process my own film rather than trust a lab for there are so few good labs left in business. When I did my own colour processing I used a Nova dip and dunk tank designed for 4 x 5 and although it is a bit crude in design it did work well, particularly the accuracy of the temperature control.
My concern lies in your finding a good colour lab in the UK to print Ilfochromes. I know from my connection with Ilford that many labs are closing the Ilfochrome line in favour of digital. I have a friend, Calum Colvin who you may know of, who always had his Ilfochrome prints made in London but has now transferred to digital partly because he lives in Edinburgh and because of the difficulty in finding good labs. I know that he speaks highly of Genix Imaging, tel 0207 734 0742 you may wish to talk to them.
I'm working on the Ilford stand at Focus in a couple of weeks so I'll talk to them to see if I they can recommend an Ilfochrome lab in the UK.