P38 Range Rover - Leaking Heater Core Fixed

Sudden leak, I assumed old o-rings were bad. I put new o-rings. It leaked straight away! I then covered the pipes in a large amount of silicone. After tightening down, it was perfectly fine and not leaking anymore.
I feel there may be a crack in heater core entry area, which the silicone has covered. There is no point
in replacing heater core, since this has fixed the issue and will probably last a decade or even more with this solution.

[@yonmusak]

I saw somewhere that a Nissan heater core fits like a treat, and has proper hoses attached to mitigate this issue. I think it was a NISSENS 73385 Heater matrix for SAAB 9000

[@PepperWagner]

Nissens 30230

[@yonmusak]

@@PepperWagner Awesome, thanks!

[@kotsioscyp]

Hey can you give me the part number of the o-rings? Thanks