Very many thanks to everybody who wrote about this query - both on and off list.
I've now learned that on their Open Day, Charnwood will be offering their Viper 3 chuck in a package, including:
Viper3,
V3ALU (carrying case),
V3FJ5 (5“ bowl reversing jaws),
V3SJ (Stepped Jaws),
V3PJ (Pin Jaws),
V3WJ (Wide Jaws),
ViperID (Insert for 3/4 x 16tpi)
for £149.
That strikes me as a good deal.
Or am I missing something
I await your views
With best wishes and thanks.
MC