Obviously it's up to the individual Mike, but I agree; if the detail isn't going to be seen, then it's rather pointless spending time and effort replicating it. However, some models do benefit from at least some detail, to give a hint of what's under the hood, and it's often more noticeable by its abscence. Bottom line - add or use what you see fit for the purposes of display.
Kevin, the white band was a Theatre I.D. recognition marking for the MTO. The yellow cowlings etc appeared as of mid August 1940, as a quick tactical I.D., and remained when the unit went to MTO.
The yellow was applied using a washable, distemper-type paint, and was never pristine, apart from when first applied.
If I can get it completed soon, the major points re markings will be in the next post in the 'BoB Bits Box' thread.