Rattle after triumph dealer serviced my d600?

So.... They've got doris for 12k service. They rode it before any work done and it was fine. They did valve clearance and changed all exhaust shims as they were out. One inlet out. So they've removed cam, changed shims etc. Put back together and it rattles like a tractor they say. Revs fine idles fine, no knocking or misfire etc.
They're baffled as to what it is. Not cct, that moves fine with the rachet, not cam chain, that's good. Hand turned and triple stripped and checked shims nested properly. They're checking the cam isn't sliding side to side but they've no other ideas.
Anyone out there got any ideas? Baffling me too. Not hard really as I'm not a mechanic! But it's a wierd one.

 

I know it's the slimmest of chances. But, you never know. Could be, like you said something daft like the top pad not being tight enough. Or a cap in wrong order. The described symptoms may jog a person's memory and offer an opinion on what to look for. Anything to help get doris home!

 

She needed the 12k service. I've no days off for the last two months or one to follow. Pure convenience. Exhaust cam was out. They've admitted it ran perfect prior to any work done as they do a test ride before the initial health inspection. so there's no way I'm.paying a penny extra. They've a good reputation and I know people who both use them and deal with them. I'm sure they'll sort it but it WILL be at their cost! I'll happily pay the 450 for the work done which includes the shims. only time I use a dealer tho.