Photo printers in the UK

My better half and take loads of photos but rarely print them as they are just stored or submitted for comps. We now want to print some out and I have a couple of questions. Firstly, should I get a Spyder calibrator to tune my screen before I send ay for printing to make sure they will look something like when I get them back. Secondly, can anybody suggest any online photo labs / stores in the UK that print without adjusting the output and ruining any processing you may have done? I would ideally like somewhere cost effective with a "print as is " tick box.

Any other tips on getting stuff printed is much appreciated.

Thanks

Geoff