Phone line troubleshooter - needs troubleshooting?

[#1]

Having problems with my phone line (dialled calls intermittently do not ring out - instead the line reverts to the dial tone or goes silent). Used the Plusnet phone line troubleshooter to report it this morning, only to end up after several minutes watching a progress bar with a screen saying  "Oops, something seems to have gone wrong". So I assume my presumed line fault will not have been reported. Is there any chance a member of Plusnet staff could pick this up? - I'm very reluctant to spend an hour on the phone waiting to speak to the Support team.

[#2]

Hi there,
I've just tested your line but no fault was identified.
Have you been able to test a different handset on the line?

[#3]

Thanks for that Adam - no I haven't tried another handset; but as I said the problem has been intermittent, so it's unlikely to prove anything conclusive. Also, the issue reported was ocurring AFTER getting a dial tone and dialling a number, when the phone should normally have been ringing out, which suggests to me it's a BTOR problem outside my home.
Any idea why the Troubleshooter seemed to crash? It did occur to me that it wasn't a very good idea for Plusnet to run a line test while the customer was using the internet, as it would almost inevitably disrupt the connection and possbily drop it, thereby preventing display of the test's outcome. IIRC from the time I was with BT for my phone service, their line test was run during a voice call to report a fault - something for Plusnet to consider? Or is there already an option to report a phone fault without going through the Help Desk? - I never thought to try.