Just revisited this and wanted to comment that the purchase of a goodybag that takes you below £3 does now trigger an auto top up. I kind of wish it didn't but have seen it happen twice so can confirm that that bug has been fixed.
Well it seems that they must be be doing something with the system maybe. Thanks for the update, the only reason I posted this summary was because so many people didn't understand how how Auto Top-up worked, and were always asking why it didn't top up whilst they were using goodybags.
Well as that's the case, it'll be good new for lots of people, if not for yourself!
Thanks very much for adding that to this post, and I'll try to find out if any changes are being made at to Auto Top-up at the moment.
Maybe other will also confirm your statement after reading this.
Thanks again. Will update with any news.