[jambo]

Phone a few places with a dyno, and explain that rather than a vague "how much to setup on a dyno" quote you would like the following:

1) A run on a dyno with an air/fuel mixture sensor to get a base setup after you've fitted the new parts yourself.
2) A short conversation about what changes should be made next if needed, looking at the data.
3) A 2nd run on the dyno once you've made those changes yourself, to confirm that the new setup works as expected, or make suggested refinements.

That should be significantly less than £500. If you're supplying and fitting the parts you're taking less of their time in the workshop, and on the dyno. Those are the expensive bits.

Ideally to make you feel better you'd have a "stock run" with it as is so you know that it's making more power at the end, but that's not all that important in terms of getting a finished setup.

Jambo