Noticed last night that the hot water tank has just started to leak and not from a fitting, Its an indirect 450x900 so 4 connections and an element. what should I expect to pay a plumber to change one?

Im quite happy to drain it prior to arrival.

god why not just change it yourself as its a stupidly easy job and when empty they weigh very little

I would say if you're happy draining it and building a car then it should be easy enough to change it. You might pay a little over the odds for the tank itself not being "in the trade", but less than the cost of the labour.

If on the other hand it's a time, arsed, warranty issue then it's 3 quotes and choose.

Halfway house maybe - you drain and remove old tank, plumber supplies and fits new tank...?

dont forget that they fill from the bottom and the hot water comes out the top. simply turning off the water and turning on the hot tap until it stops will not drain it. if it was fitted correctly there should be a drain valve on the lowest fitting.

to drain the system down properly.

turn off mains water.
turn on taps until they stop.
now drain off the takn from the lowest pipe.

now the tank is empty you will have to drain down the central heating from the drain valve.

once all that is drained down you can take out the cylinder and replace it yourself. you can buy them in wickes or b&q.

put the new one in reconnect all the pipes. turn the mains water back on and bleed all the radiators. dont forget to put rust inhibitor back in the radiator system tank (it will be the smallest one in the loft).

would say region of £80-100 for a tank and £100-150 for some one to fit it, its not outside the DIY'er and available from B&Q etc. but as for not heavy be aware thay can be if in a hard water area, when i took mine out the bottom 9" was full of scale!!

Yup... easy to fit yourself...

Although its an ideal excuse to fit a direct hot water tank!! :p

(thermal store)...google it