I have a cunning plan!
It seems you can get adaptors, to allow you to fit bar end shifters, to your handlebars (Jtek Special Thumb Shifter Brackets for 22.2 mm Bars - Black).
This means I'd be able to still use my current Shimano bar end shifters (Dura Ace 9 speed triple), and no need to change the front mech. These may not look as neat as proper flat bar trigger shifters though, but stocks of 9 speed shifters (and comptible front mechs) are rarer than hen's dentures at the moment...
butterfly by [url=https://www.flickr.com/photos
Jtek Special Thumb Shifter Brackets for 22.2 mm Bars - Black
Jagwire Rocket II Cable Adjusters for Fixing to Plain Frame/Headtube Boss - Per Pair
Genetic Zygote Handlebars - 31.8mm Clamp - Black - 600mm
Dia Compe DP-7 Disc / V Brake Levers - Black / Silver
Clarks Stainless Steel Universal Front & Rear Brake Cable Kit - W8012
Clarks Stainless Steel Universal Front & Rear Gear Cable Kit - W8009
£110 or thereabouts.
I do think it'll be money well spent if it means I can get out and enjoy cycling again, without complaints from my neck!