Sorry to cause confusion H, I tagged another topic onto this thread rather than start a new one, it's 2 years old - apologies.
It's just this, you can squeeze it in a very small gap, it just softens/deadens the sound/vibration. https://www.ebay.co.uk/itm/253790072629 If needs be you can cut out some of the wood it's hitting.
Thanks for link for future. re: wood - that's right, relief is needed, but it's not a 5 minute job, just too large to tackle right now.
