[sk546]

Well, first off congrats on your recent purchase and soon to be collection, hope you enjoy it.

Onto your query, Hybrid and Pure are almost identical apart from in Pure, A/C is deactivated to increase range so whichever you select will try and utilise the battery as much as possible until its empty and switch to petrol unless you request more power than the electric motor can provide and the ICE will kick in to fill the gap.
The most efficient way would be to charge it at both ends of the Journey provided there is the option to charge at work. If that is possible, you will likely get 95% of the journey done on electric and use very little petrol.
If charging at work is not achievable, experiment with selecting 'Hold' when on motorways so it only uses the ICE at higher speeds and leave the battery for all the other stuff. Driving in electric at higher speeds tends to utilise alot of battery power when its probably more efficient to use petrol.

Hybrid driving requires a little bit more concentration and planning that your standard petrol/diesel driving as knowing when best to kick into petrol or utilise the hold mode takes a bit of getting used to but once you get the hang of it, the advantages can be huge. On journeys between 25-30 miles each way and being able to charge at both ends, I've achieved economy figures approaching and sometimes exceeding 200mpg. Very useful.