Botched Aux Heater job needs fixing

[yeshu26]

VW Sharan 58 plate BVK Engine code.

Following picture will put things into perspective.

The Aux heater has been totally removed, as it has a broken pipe and kaput electronics. What mechanic should have done, he should have taken two long "coolant grade" pipes, and joined the front and the rear heating pipes, so that the water flows all the way to back heating systems and comes back.

This was done about 2 years back, but I want to fix it now.

1: Please advice on what kind of flexi pipe I need, and from where I can buy it? must be OEM grade and withstand coolant material and temperatures.

2: Since the rear heating system had no coolant water running inside it for about 2 years now, is it possible that it would have been corroded?

3: Can I buy a long pipe like this, and cut to requirements? What will be the consequences?

https://www.ebay.co.uk/itm/Auxilliary-heater-hose-pipe-Sharan-Alhambra-7M3819674A-New-genuine-VW-part/121549406414?epid=743289787&hash=item1c4ce8c0ce:g: fBMAAOSw8d9Uv5k5:rk:2f:0

Many thanks

Himmy