Before I ripped the 3k out, I checked the Extractor fitment, given that they are notorious for hitting things in KE10's.....
Perfect fit! It's touching the side of the Toyoglide, but the K50 is about 70mm narrower, so it'll have plenty of space in there once I swap the box.
There looks like ample space for the starter (shouldn't even need a KE70 one), and the Idler is also clear on full stroke, plus they fit up nicely with the Dellortos. I'm fairly sure they're HM's for those who want to know.
*EDIT* I just checked my correspondence with the guy I bought them off, he said they were HM Headers (Perry might be owned by HM now)> I'd assume they are the HM38's off their website. I'm blown away at the fit!