Cabbage smell when wind blows

[Marion58]

I have Worcester Bosch Green star. LPG Combi. Kept in walk in store room on back wall. Ever since it replaced an old boiler of 13 years if it's windy and blowing in certain direction the cupboard smells of cabbage bad eggs. With this very bad wind the cupboard smells nearly all the time. On first service I mentioned this but engineer didn't take any notice of me. Put up with it for several years now but it's a bit too much with the persistent wind we are getting. Our previous Combi had no smell at all. It shouldn't be smelling obviously but at a loss to know what causes it. No dead mice etc.
Thanks for any advice.

 

[Lou]

That is not great is it?!

Have you checked it is nothing outside? Is there a factory or anything that could have a smell that could blow over?

 

[Marion58]

That is not great is it?!

Have you checked it is nothing outside? Is there a factory or anything that could have a smell that could blow over?

 

[Marion58]

Hi, nothing outside we live in middle of nowhere. Not a dead mouse. It's done it since new. Old not a problem.