Hello Marcus,
I apologize for the delay in responding; it has been a very busy last few days.
The browsers used for testing are Firefox (38.0.1) and Chrome (43.0).
I look forward to testing the version 1.7 when it's ready.
Please find attached the xml dump of the singular/plural question with letters as requested.
Just tested item 1 again (from Chrome) and obtained the following error:
Notice: Undefined index: p1 in <moodle_home>/question/type/gapfill/question.php on line 244
The debugging is set to Normal.
However, on the production system it is now set to Minimal until these issues are resolved.
Please note that as mentioned previously, this occurs with Moodle 2.8.5+. The problem does not seem to occur when tested on Moodle 2.9.
Regards,
sali