VFR
As long as you are employed on the books of the company as a part time driver / cleaner / labourer and stick rigidly to the ANO with regard to Weather and rule 5, and as long as you fly company personnel around then you should be OK however, many people have been there before you, and very quickly you fall into the trap of the occasional flight falling under public transport rules at which point you are a very silly person
Is the ranger on N or G reg
Either way watch your back and dont tell all and his wife as jealous types will have it in for you.
Best of luck, and grab as many free hours as you can.