Hi guys,
Thanks for your responses so far.
I've removed the engine from the mower and decided to tip the oil out into a glass beaker. A whole 100 ml was inside. The engine has a tag on the recoil starter that shows a oil symbol and it has a tick showing thus meaning that it has oil inside. Normally engines that have no oil in them have a warning label somewhere attached saying "Requires Oil prior to starting".
BTW the previous engine I purchased from the same supplier a week earlier had a full crankcase of oil in it, thus why I just tipped the mower backwards and saw oil come up the filler neck quickly.
I'm really starting to wonder who's to blame here as I'm sure had I put extra oil in it this engine would still be running sweetly now.
Now with Christmas on our door step I'm wondering how long this is going to take as most mower shops have already shut for the long break and the one I bought this engine from won't re-open until mid January. I'm going to contact Briggs' Head Office tomorrow and see how they would like to approach this situation and if I can get an engine direct from them without going through a dealership outlet.
Cheers,
BB.