Installing a new coil in a 200lt galvanized cylinder

[JDPSpain]

The internal coil is corroded (leaking) Its an indirect storage cylinder so there's no health problems...But changing
the cylinger is complicated. I'm looking for a flanged retrofit spiral coil with flange. Any suggestions? Thanks Justin

 

[JDPSpain]

The coil is obviously corroded so I intend to put a new indirect coil and install it in a similar way as in the attached photo and to plug off the existing indirect connections
What I need is where to locate Essex type flanges in large size to adapt to the cylinder which is about 2mt high and 75cms wide galvanized
The reason not to change the cylinder is that it was installed during construction and is very difficult to exchange without huge pipework and brickwork alterations.
Impossible to put into a lift and limited room in stairs (5th floor)

 

[Gasmk1]

coil I fits into the immersion boss called a hot rod they work but not great