The Dilog 9073 appears to do all the necessary tests from continuity
through to prospective SC, RCD testing and more.

At around gbp 450++, is it a reasonable choice? Any other alternatives
of note?

Are they sold with a test/calibration certificate or are you expected
to have them checked immediately after pruchase?

The 9073 is specifically advertised as a '16th edition tester' - are
there any changes to tests in the 17th ed (due 2008) which this tester
won't be able to handle?

most interested to hear any and all opinions

TIA.