Cam Chain Tensioner woes

Well, I'm assuming it is them anyway....

A little while back, I started getting a lot of vibes and a thrashy chain sound at 5k rpm onwards, which is annoying if you do any motorway mileage. Have popped the cam chain tensioners out and put back several times but now have a bad rattling sound at 4.5-5.5k rpm with accompanying vibration. I'm at a loss as to why this is - both tensioners seem to work correctly when removed (had to replace the bolt on one with a slightly longer one as the previous owner had managed to strip the top part of the thread ). Both are smooth throughout their travel. Is there something else that can cause this kind of noise/vibes? Getting a bit annoyed with constantly trying to sort it out, only for it to return once the engine is warm. And whoever designed the airbox needs shooting, no questions asked and no last breakfast

Will swap them over when I next get the chance to see if it is a chain or tensioner problem but is there anything else I should be looking at? Is it likely to do any damage?

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