Thanks to everyone who has responded, it was really re-assuring whilst sat in various laybys between Poole and Cornwall! Anyway back home safely now! I hope its ok, but just wanted to re-cap on the issues including whats happened on the last part of the journey to see if anyone could throw any light on it:
Ok so Left Cornwall and got about 5 miles, hit a big pot hole (Left Hand Side) and shortly after the engine cut out. The engine would crank but not fire. Called the RAC and sat for about 30 mins and looked for inspiration on the forum, found a link about the intertia switch and pressed it....hey presto is started.
Pulled off onto the A30 and was motoring along for about 2 miles when the engine coughed (revs dropped and popped back up), and all was well for a further mile until it died completely.
Pulled over and sat considering options. Hit the inertia switch again but it didnt start, realised the LPG was still engaged so turned it off and presto it started! As the engine stalled it threw an alternator Fault and Gearbox Error, however both of these cleared once i'd sat with the engine running for a while waiting for the RAC.
RAC rocked up and concurred this could be a faulty inertia sensor and advised me to continue carefully.
Journey continued another 40 miles to the nearest services, shut the engine down, came back to the car 30 minutes later, restarted with no issue....great.
Continued another 30 or so miles and the engine died without warning. Trying to crank the engine resulted in it turning over but not firing. Pressing the Intertia switch didnt solve the issue immediately, but several start attempts (on petrol) pressing the inertia switch between tries, the engine started.
i began to wonder if the issue was related to the LPG system, so i ran the final 50 miles on petrol, i got about 45 miles with no issues until i stopped at a roundabout and the engine died again! I followed my hasty restart procedure (bearing in mind i was blocking the road at this point!) and eventually it restarted.
Managed to get the final 5 miles with no issues and home. When parked up i let the engine idle which it did with no issues, rock solid, i swapped to LPG and blipped the throttle to 2k RPM to complete the changeover, again no issues. Very odd!
I should state the engine is abourt 15k miles old (it was a recon top hat engine) and has a multipoint Zavoli system fitted. It generally runs perfectly, not rough at all, changing between petrol and LPG (i run it mostly on LPG) happens with no issue at all.
I think during the last 150 miles i've deduced the following:
1) The fault doesnt seem to be related to the LPG System directly as the issue also happened on petrol mode.
2) The successful start using the inertia switch may be a red herring as there is no Inertial Switch message in the display. Also with the engine running, tapping the inertia switch (the trim panel has been removed) doesnt kill the engine.
Could this be a failing CPS? I've heard this can cause this sort of symptom and this isnt always logged as a fault code?
Sorry for the long waffly post, but any thought would be appreciated.
