Strange reflection/refraction

[Furnace]

Hi all,
I'm rendering this car within a lit HDRI dome, I'm getting some really odd bright reflections from inside the glass, I've done the obvious stuff like tried turning off 2 sided, turn off fresnel etc. but it's still there, I'm guessing it's maybe something to do with BDRF, any ideas?

Thanks in advance for any help.

Cheers.

[Furnace]

Ahhhh - fixed, was a double object overlap!