Chris's idea worked for me...
But id reccommend spending a bit more getting a good company to re adjust it. I know Abbey not answering their calls at mo.. Fridays not best day to do this.. but leave message and call them sat morning or monday.
In meantime just stick a bit of sticky sided rubber / padded seal (heat resistant preferably) from halfrauds on bottom on ur vallence to stop the noise when exhuast hits