"Have nothing to do with British Gas. They are all *ankers."Except that the missing letter was left in. I omit it only out of consideration for any users of cybernanny software.
Even more amusing is that the email was transcribed by a senior relative (female) from an oral communication.
Anyway, having finally got a straight answer out of a very nice lady at British Gas, who took my details over the phone and gave a quote even higher than the too-high quote received a couple of days ago, the contract has been cancelled.
To save the effort of any smart alecs out there, the missing letter was not b, c, d, h, l, r or t.