Odd one this - I expected the overcharge, didn't expect that they
couldn't fix it or that I couldn't subsequently work out how it was
calculated.

Basics - rushing back for a train at Waterloo I got through the gates
before it left but just missed it (it left a minute early, I reckon). I
then went back out through the gates (touching out on the way) and took
the Tube back to Z2 rather than wait inside the barriers for the next train.

This should have cost Z1-Z2 tube (£1.80) but I was instead charged
£3.20, the remaining amount on my daily cap. On querying this with the
ticket clerk, he said that he couldn't put the money back on because the
system was claiming I still owed £1.10 somehow. Here's the printout he
handed me:

* 14:31 Chiswick – Waterloo NR12-19 £0.00
* 14:40 Chiswick – Leicester Square £3.10
* 17:36 Pre Pay Exit Waterloo NR12-19 £0.00
* 18:18 Waterloo NR12-19 – Turnham Grn £3.20
* 18:18 *** cap applied ***

Z1-Z3 cap is £6.30, so £3.10 + £3.20 covers it. My bus home was duly
zero-rated.

Now, can anyone explain how the system came to work like this? I must
say I'm rather baffled by it.

Tom