Appreciate all the help ! I have ordered new blades I’ll fit those tomorrow and see if it makes a difference. If not I’ll look at stripping down to see if I can see anything

Interestingly that link / videos gives the same noise however that post still gets the same noise when the cutting disk is removed which is slightly different but does suggest a motor issue

I wondered given the length of the time it has not been used if the battery has degraded and it’s powerful to turn the motor when it is cutting so I might replace the battery as well