Disco 1 300tdi rear core plug replacement

Hi guys been a while since i've been about but started a new job so not around as much lol. anyways today on the drive home i noticed blowers were cold so kept eye on temps and got it home. when i pulled up i popped the hood and seen/heard steam/water near the back of the engine where the heater pipes run figured i'd rubbed through and split a pipe. well the pipes were whole so i filled up bleed and went for a spin short spin about 2 miles got back opened up the res (slowly after letting it get rid of pressure) topped up and put cap back on. rev'd it a little from in the engine bay and it made itself visible water spraying from the back of the head to the firewall! so im assuming that would be the core plug.

my big question here is now im working i dont have time to take it apart and do it myself so what would be a reasonable price to be paying for it to be done, or is there someone on here who would be interested in doing it at a reasonable price.

Thanks for any reply's guys

I've got a horrible feeling it's engine out to do that one.?
Hopefully I'm wrong.

Faster to take the head off BUT are you sure it's the core plug ???
I thought it was on mine till i f000000000ked the motor turned out to be the pipes from the heater

For a quick FIX you could try stuffin some E metal in (putty) Till you get a new gasket

Think the core is in the block not the head.
Best get a mirror and a torch to confirm exactly where it's coming from.

No there is 1 in the back of the head !