Hello Rolf, There are a number of UK suppliers of Commando parts and the availability is excellent. Have a look at the Andover Norton site, it includes a full list of distributors including one in Norway.
http://www.andover-norton.co.uk/If you are looking for non-stock parts such as stainless or performance, then I would suggest looking at RGM Motors, Mick Hemmings and Norvil.
Smiths SSM speedos are no longer available new. There are pattern items but I have no idea how good they are. Once again, there are a number of reliable repairers but I've never used them by post so hesitate to recommend any particular one.
Do you ever see 'Old Bike Mart' ? There are usually four or five speedo repairers advertising there.