I was going to Chatham today, from Z3 West London, and thought the
cheapest fare might be to get a Travelcard and use that as far as
Bromley South (where all the Victoria-Chatham trains stop, so no
problems with 2-ticket rules) plus a Bromley South to Chatham CDR.

The latter was 7.20 when I looked online.

I explained this all to the chap at the ticket office, after he'd tried
to sell me a significantly more expensive dedicated day return.

"Oh, you want to do it like that, do you?" He asked, and looked
something up in a big book. The train was due so I paid up and ran.

He had sold me a Z6 Travelcard [which was correct in any event] plus BZ6
to Chatham CDR which was charged at £8.00.

Why is that more expensive than the Bromley South CDR, particularly
considering that Bromley is on the inner edge of Z5?

Q1: Did he deliberately (or even accidentally) diddle me out of 80p?

Q2: As the station nearest BZ6 is actually St Mary Cray (or is it
Swanley, the online map has a big ATOC watermark obscuring the exact
boundary), and the train I caught stopped there too, how much cheaper
yet is a St Mary Cray to Chatham CDR?
--
Roland Perry