The output from my idle valve is 22mm, the input to my manifold is 10mm. I have no access to a lathe. Is there anyway I can simply make some sort of adapter (plumbing supplies?) that will let me connect the two up?

Regards,
Dave

would this be any good?

Adaptor

You can get them in b&q etc

I love this site

Thanks for that.

no probs, if you buy a yorkshire one/pre- soldered it's beaded for you too

Should have linked this first - click me

Note the dimensions on the reducer refer to the inside diameters! The OD will obviously be a bit larger.