Apologies for not replying sooner. Nope - used the update button in the email client (using 2 IMAP accounts).

Removing all but a single location seemed to keep things reasonable. I think it was still doing the updates but the download size wasn't excessive and my PAYG balance wasn't taking a serious hit. With the full list of locations I originally had checking my email was costing me nearly GBP0.80 each time!