Oil and fuel will be fine, not sure about the air. I suspect you may not have a standard 200Tdi filter as from what I can see of your engine bay it is upright in the N/S corner, which is the same place as a N/A or a TD filter (not 100% sure of the TD position). These filters are cartridge type filters but they are smaller than the 200Tdi Defender or Discovery ones, but I can't be sure. If you want to take pics of all the aspects of your engine bay then I might be able to tell you more.
it looks from the picture like a reasonably good conversion though, so that is a good start!