Overkill
It's all jolly high-tech, but here is a lower-tech replacement.
Whilst at home:
1) Use the PINsentry calcumalator and your debit card and follow the instructions supplied by Barclays for generating the magic numbers needed for the online banking site.
2) Write it down on a slip of paper. I find the back of the perforated receipts you get from the newsagent to be ideal.
3) Repeats steps 1 and 2 until you have run out of space on your paper.
When out and about, without your PINsentry bulkomatic pocket filler:
1) Go to the Barclays site. When prompted for the magic number generated by the PINsentry type in the first number from your piece of paper.
2) Tear off and discard that first number from your piece of paper to avoid accidental repititious use.
It works for me. YMMV.
Biting the hand that feeds IT
