If it's anything like my Berlingo, there's a number of "screws" dotted
round the outside of the undertray. They turn through 90 degrees and pop
out, and there's one towards the rear of the undertray in the centre.
21mm socket will take your drain plug out.
Get yourself some oil filter pliers like these (no connection with seller)
http://www.ebay.co.uk/itm/GOODYEAR-TOOLS-ADJUSTABLE-12-OIL-FILTER-PLIER-
PLIERS-WRENCH-REMOVAL-TOOL-HEAVY-/110874575859
It'll be the best £5.39 you have ever spent. I've not found a filter they
haven't shifted with complete ease yet..
--
Mike P