Thanks for your reply.
I hope the attached image is more clear for you. When I power the multimeter on I switch it to V, then press the orange select button to toggle into AC mode, and the first reading can be seen on the image to the L - the Middle image is the second 'range' option, and the third is the one that shows 00.13 (although to be specific, the '3' is not solid, it toggles constantly between 1,2&3.
I hope this sheds light on the Multimeters behavior.
As mentioned already, can one take a 01.19 VRMS reading and deduce it is a measurement of 1.23 VRMS being that it is so close and taking into account the cable used or the meter not being 100% accurate? Because I do not need 100% accurate - I just wanted to establish whether a -20dBFS 1kHz sine wave is equal to +4dBu.
As an experiment I changed the -20dBFS to -19.77 dBFS and got a 1.277 VMRS reading.