What is reasonable price to pay for a good work

Hi, lads

I live in a 18 years old detached 100sqm bungalow approx and have oil heating with 12 rads.
The boiler works well but as any other old machine just swallows the fuel so it is time to replace with a high efficiency one.
As I’m on the verge of getting granted a full planning permission for a large shed to a home study and play room conversation and it’s important to get the rooms warm during the cold months, I’d like to connect it to the existing external oil burner heating system.

The idea is is to fit 5-6 rads in the conversion (the unit is about 66sqm), connect to the existing system (approx 15m away), change the water cylinder to a larger and efficient one, add 3 zone heating controls and upgrade the boiler to a higher capacity, high efficiency one.

Do you think a budget of €5500 will cover this?