On the side of the block. Side facing the front of the car. That great big blue thing just underneath. Can see from underneath much easier. In the same sort of position/angle as a the ford 1.6 and 1.8 zetec engines.
The oil filter is on the bottom of the engine screwed upwards into a recess in the sump. The recess means that only about one inch sticks out making it all but impossible to see from the side or front. You need to be under the car to see it. It is to the front driver side of the engine, under the alternator and air con compressor. It is possible to reach sticking your arm under the front spoiler, but as I say, knowing what you're reaching for is difficult without seeing it! Changing it is a doddle with the proper wrench and it won't lose much oil when removed. I didn't change the oil when I changed mine, just topped it up with 1 litre afterwards which took it pretty much to the top mark on the dipstick.