Nuevo rear passenger tray

Just a guess, but - assuming that the 5 year old is sitting in one of the rear seats, with the table in front, I'd try using a rectangular plastic tray which has a lip (about 10mm) all around; place the tray on the table, with its longer edges parallel with the seat (i.e. at right angles to the side window); I'd cut out two slots in that rim, near the corners of the longer side, into which I'd slide one of the jaws of a strong metal spring clip (as beloved by market stalls - which is from where I bought ours). The tray can thereby be secured to the table with the clips, in front of Junior. It may not look pretty, but it should keep things in place, especially if covered with a non-slip mesh.

On our Nuevo ES there are 2 tables: a small one, which is stored in the wardrobe, and the larger one which, whilst demountable, is located in front of the seat-belted rear seats. That table has a high-level mounting rail (such that the table can be used as a table by the persons seated at it) and a low-level one for when the table is used to form part of the bed. There is no alternative storage for that table, and it remains in place when travelling.

So there cannot be any issue with its location or use whilst travelling, I believe. There is no mention of it in the handbook - which has pages and pages of cautions! (I was amused to find one sticker warning me not to drive the vehicle whilst the blinds are drawn closed over the windscreen and cab windows!)

And as Paul says, coaches have them, for the use of forward-facing passengers.