extras
You are really fleeced with these prices,all of them.Pressurised water system will cost around €20.-(twenty)extra for a stronger pipe.22 mm instead of the standard 15 mm.Standard taps are the same.Check any DIY shop and you will see that a shower running on pressurised water costs less(!) than the bucket -in -the- attic-with-a-pump type.Because you need no pump.For which you pay.
A double socket costs around €5.- incl.switches.Etc..
A factory lined immersion tank insulates much better than a standard glass wool jacketed.And costs around € 50-100 extra.
But when you go for a pressurised system than you need no immersion heater at all.Just a proper combi (condensing)boiler,the cheapest is from Vokera and costs €1400.-incl. VAT,model "Synthesy",available from most plumbing centers.
It would safe the odd Firebird and plenty of running costs.And a chimney for a few € 1000.-.And a min. of 20% of your energy bill-which is nearly an average monthly mortgage payment -per year!
These (very strong!!!) plumbers here in Ireland rip the people off for a quick € leaving them with bills to be payed for generations.
It would spare you some electrician costs as well for the immersion tank and a power shower.
Extra heating zoning safes considerably,but go for the room thermostats or the radiator thermostats and not for the one-per-floor thermostat.There is always a room that needs less or no heating at all.For example why heating the bathroom over night-a timer combined with a thermostat is a once off investment.
And tell your builder to insulate all pipes,especially those buried in the floors,you won't be able to do them after wards.Costs are around €1.- per meter for material.
It would be worth it for you to check
www.irish-energy.ie/
It might be worth it as well to engage an engineer to supervise your builder,his building standard and his prices are outrages.