With only 6 to do - get yourself a pair of double-bowed clippers, tie them up in a head harness into a corner of two hurdles, and off you go! In shetlands you should see the break between old and new growth quite easily, so just shear in there!. Also you can hand-roo them, if not all in one go, but just what comes off easily.
It is really not worth for a shearer to come out and set up for 6 sheep, especially now that they are getting busy.
Or get them to a neighbours farm when they do theirs.