Dont you just hate it when you spend absolutely ages looking for a photo, and then when you find it realise that theres a lot more work to do....

Came across this photo last night, http://www.jason-cottage.fotopic.net/p51561520.html, which gives a pretty clear view of the top of the tender. In the process confirming what I was afraid of that the recess cut into the back of the tender does have an open top (all be it with a grill over the top). The problem is that with a thick sided plastic moulding, even drilling it out would result in a much too thick side.

My plan here then, is to draw up an etch for the grill which will be glued on as an overlay to the top of the back, and not model the hole under it.

The photo also shows what I was originally looking for, in that the water filler cap has been replaced with two flaps (one on each side) which will now be added from 10 thou plasticard.