Gentlemen once again thankyou for your invaluable input. I was considering this but it's clear would have to shim both steerer and bars.

Vintage 9.5 cm 3ttt Record 95 x 26.0 x 22.0 mm French alloy road stem 7 mm Allen | eBay

I have no reason to change the bars as they're the right width (in fact the same bars are on the Grand Prix and Europa with 95 GB stems) so will look for a GB stem in 95mm to suit.