Finally got around to doing the oil change .....
![Embarrassed :-[](https://clubjazz.org/forum/Smileys/SoLoSMiLeYS1/embarrassed.gif)
Turned out to be very straight forward. 6 philips metal screws for the undertray at the sides + 2 plastic fasteners at the rear. The plastic fasteners were a little damaged but went back in and hold the tray absolutely fine (at the moment!) but I'll get a bag of those mentioned earlier in the thread so I can replace them anyway.
Thanks to all who responded to my query.