Radley models A STOCK - help please,

I am currently part way through building an A stock unit (to be numbered 5062). It has been a joint project with my dad (he assembled the chassis while so far I've concentrated on the bodies) and was started just over 18 months ago but has been on hold for almost as long. However I resumed work on it last week and considering this is the first rolling stock kit I've worked on things are going well. First of all I'd like to thank metman for posting the thread he mentioned above, this has been very useful indeed. A few other comments and questions:

It is the chassis for the driving motors that need to be trimmed. For some reason the DM body is around 1-2 mm shorter than the trailers. As the unit I'm building has seats, which will be attached to the chassis so the interior is accessible in case of damage to the glazing, the DMs may need to be fitted with a pair of retaining brackets (one in each double door vestibule). Some of the seating on the DMs will have to be cut out where it would otherwise cover the screws which attach the bogies to the chassis.

The door indicator lights are at the wrong end of the trailers compared to the arrangement of the bulkheads. Therefore I have removed them and am planning to paint them in the correct position. I don't believe I'd be able to accurately position such small pieces of plasticard and want to avoid making them oversized.

The unit will be coupled using bar couplings fitted to a plasticard beam which is attached between the vertical parts which hang down from the chassis ends (is there a technical term for those?) On the real stock the couplings were fitted further back but it still looks reasonably realistic and is quite simple to make. I'll have to see how sturdy it is however. I'll probably fit this arrangement to the cab ends to allow the unit to potentially form part of an 8-car in the future, though that would mean there will be no room for the wedgelock.

Finally, the kit was purchased as a 4-car set which included one tenshodo motor bogie. At first we were looking at replacing this with a black beetle or similar but this would require major modifications to both the chassis and the resin bogie sideframes part which is designed to fit a tenshodo. A pair of tenshodos would be a much simpler option but this would need an extra resin bogie and a different kind of plate which fits to the chassis where the bogie is mounted. Neither of these parts are listed on Radley's website but does anyone know whether these would be available? I realise it would be better to email Radley Models and we will probably do so but I just thought I'd ask here while I'm posting this.