Yes it is a great site alright
I would fit a stove anyday over an open fire/backboiler. Take it from me in five to ten years there will be no open fires going into any new builds.
If your pipes are inch there is no need to change them. You need atleast inch pipes for natural circulation to be successful. Check your cylinder, can you tell me how many connections are on it? 4 or 6?
We fitted a stanley last week, supplied cylinder,pump,flue elbow,2 ft of flue, (same colour as stove) pipe stat, piped stove into heating system etc and the cost was just over €1400 inc Vat. It took 2 days but the cylinder was 3 ft from stove so less materials.
Whatever or not you could do it yourself I'm afraid I can't answer because I don't know your DIY skill level, however I would advice using a professional as these appliances have to be safely fitted.
Edit: sorry, just re-read your post, Cleaning the chimney is quite easy and if you have brushes, than do it your self. Just besure and hang an old sheet over the opening of the fore plaxce to minimise dust/soot entering room.