Plastic Smell when lighting stove

Hi,

Bit of a strange one, the last five or so times when I've lit my burner its been given off a plastic type of smell which only lasts for about 15 minutes and then disappears once the stove is coming up to temp. I've given it a really good clean (to rule out dust) and removed the baffle plate and cannot see any signs of a build up of creosote around the flue pipe. The stove has been running all winter, but not every day as its been fairly mild. Always have a hot burn with wood under 20%. I know that in milder conditions now spring is upon us, the draw is not as strong but I'm stomped as to what could be given of the smell. I've got the installer coming out next week to take a look and give it a sweep which will be its first once as its only been installed for 8 months.

Any ideas?

The burner is installed into an existing chimney that has been lined, insulated and fitted with a cowl,I also have a register plate which would prevent any fumes from coming down into the living area if something was leaving against the pipe further up the chimney. So its very unlikely that a foreign object has found its way in.

Yeah there are

That was my first thought and I did find a small piece of Lego under the stove but it wasn't that giving off the smell. It's strange that the smell disappears once it's up to temp

So after cleaning the top of the baffle plate and two hot fires, I lit the stove tonight and the smell is getting milder and not lasting as long. My thinking is that whatever is causing the smell is slowly burning off.