I finally got around to changing the oil filter on the copen and what a drama so I thought I should share my story here in case it can save some one else some trouble. Whom ever serviced the car previously had installed a filter twice the length of the normal one so it could not fit out through the gap in the engine mount. To get it out I had to remove the lower inter-cooler hard pipe and soft hose. The pipe is held with 2 12mm bolts and has an oring. Once these are off the filter could be maneuvered between the exhaust and inter-cooler then past the bumper and cross member. The oring is a pain to keep in place while refitting the pipe. If it is stuck to the pipe as mine was don't pull it off like I did!