THOR 4.0 plugs

Just traced a missfire & rough running to cyl 1 plug inner insulator being cracked in two, lucky the hard bit of ceramic didn't decide to break free & damage the head & piston.... Bought 2 replacements from LR dealer today at £8 ea.

Plugs are the LR reccomended Champion Platenum items, does anyone use anything else?
Apparently the management system gets upset with anything else according to RAVE, not sure as to why as the THOR 4.6 uses the same system & LR reccomend a different plug...??

Also are they suitable for use with LPG?

Have checked the others & they appear fine, were replaced around 12k miles ago, allegedly supposed to last for 48K.......

If you have a craked plug insulator and you run LPG,I would suggest you make sure your airflow meter,oxygen sensors and plug leads etc are all spot on.That damage is most likely caused by a weak mixture,common on badly set up LPG systems - which usually run too lean rather than too rich.
You dont need the posh platinum plugs,just use NGK BPR6ES instead and change them every 12-15k.
What is important is to get the LPG ECU trimmed to provide the same fuel trims as it would use on petrol,something that not many LPG places seem to understand....