The boiler at the time was I think just short of €1000 (inc VAT). I think the plumber came to €1300 for 3 days work. A little over the odds, but he did work for me before and I was v. happy with the quality of what he did. No messing around and not finishing the job. This was about 3 years ago.
The hot press work was done by the best Dad in the country!
My overall gas bill (cooking, heating and hot water) comes to about €45 per month; c.1500 sq foot house, 1 teenager (never out of the shower), 1 proto-teenager (never goes into the shower!) and 1 adult (washes normally!).
The only real downside is it can take a while to fill the bath; we rarely use baths so that's not a problem for me.