good price? labour only to replace gravity fed system with combi

A question about : good price? labour only to replace gravity fed system with combi

I have found a leak from our hot water tank which has been leaking for a while now!! noticed due to a stain appearing on the ceiling!! anyhow. we have a gravity fed system which we are going to rip out and replace with a combi. we have a quote of Ј750 for the work inc bits (not the boiler timer and flue) he says it will be a 2-3 day job. I am assuming that this is ok? or actually really good?

Just worried that I miss something and it should have been cheaper! sorry to ask but I need to keep a check on the pennies!!

Best answers:

• If you add on Ј800 for the boiler timer and flue you are getting a very good price, but you must be sure the system is being properly cleaned out and it's worth coughing up for a magnetic filter to protect the boiler and maintain the hot water efficiency long term.
  You have not mentioned which boiler you are getting. They are just a few to steer clear of, but most are OK. Also what size is your house ? A 24kw boiler may be fine for heating, but hot and water performance is often barely satisfactory, so if it's a 24kw being recommended then its worth the extra for a 28 or 30kw, but no higher.... Unless it's a big house of course.
• its not a big house!! 3 bed semi. so it has 9 rads, I have been looking at a 28-30kw one
  and the system needs to be cleaned as aparantly the toilet overflow is too high (or low can't remember) so when the system was switched off the water ran blue in the kitchen as it was coming from the toilet!!! so that is being sorted too.
• what does a magnetic filter do?