Now done just 600 miles in our +4 and have been driving it much along the lines others have said here - mainly on A/B roads changing gear, maintain reasonable revs and not allowing engine to labour. This weekend was the first time I had dropped a gear and overtaken another car maxing about 4 k revs.
I have just booked 1,000 mile check up service and will get oil changed then also. Probably not strictly necessary but, like Adrian, believe an early oil/filter change is better than not.
Just out of interest, first fuel fill brim to brim (267 to 570 miles) shows 39 mpg. Most importantly, really enjoying driving the car though, hope you are too