I have tried and failed to work out if you can select large numbers of files and then change a single label. In this case I want to blank all of the 'album' titles. Can anyone advise? is there something obvious that I have missed?

Thanks for any help.

Yes, you have missed something obvious:
In the tag panel you find the option <delete> in the dropdownlist for every editable field.
Select this to delete the field.

No, I hadn't missed that. I had selected all of the tracks, then 'blank' in the tag panel (there was no 'delete' option) but then couldn't see how to intsruct the programme to go ahead and make the changes. I am sorry if I am being thick, it is probably because I am ancient.

Sussed it!

MB