I've had it for about month now and a couple of questions.

1. Are there any back-of-a-fag-packet ideas about whether the use of the
'ECO' button makes a worthwhile saving given the extra convenience of
quicker hot water?

2. The hot water dial on the boiler has an 'e' between settings 4 and 6.
The manual does not mention it. Is it considered to be an optimum
position? What does it stand for?

many thanks