You've done very well there my friend!!
The goggles are Mk VIII model which went into service in 1943. They would have been worn mainly on the 'C' type helmet as the 'B' type of the Battle of Britain period was by then obsolete.
The frame is the correct RAF colour of grey painted brass, the kicker is that there should be an 'AM' (Air Ministry) stamp on the leather underneath the central hinge of the frame.
This may be very faint due to the wear on the goggles, so look closely!!
I personally would leave the stitching in the 'as found' condition, but if you want to wear them, then you can get them re-stitched at any saddle makers store (there's loads round here!)
As to value, i saw a pair of almost minty goggles for sale last week up for 250 quid!! Here's mine and a pic of how the whole ensemble should look.(Which i wish was mine!!)
Kind Regards, Ned.