Got a new internal door handle in the post from Canley Classics. At first I thought "it does not fit." The thing looks identical to broken one but ....
The part that fits over the shaft is correct size to hold the shaft but oversize to fit through the escutcheon.
On talking to the ever helpful David Pearson it seems that the new handles are bigger and better. I will have to enlarge the hole in the escutcheon. If I bought new escutcheon as well the hole would have been bigger.
So I have little bit of fittling to do. I should be used to that by now after 16 years as a Vitesse owner.