apologies, but for some reason could not manage to list this in the n'porium.

I have a Graham Farish 372-676 4CEP four car EMU 7126 SR multiple unit set, in green with warning panels, never been out of the box.

anyone interested ?

if you are please PM me with an offer.

MODs, not sure if N'porium is working or if I didn't do it right.

... and there was I half expecting a "Help!" ping from you Alec!   Glad you've sorted it, otherwise I might have considered knocking up some sort of mini CDU in a little box, just to drive the 4 motors of the scissors. 

Presume that's the source of the model tram and car scenes at the beginning of "Later With...."

Many thanks, soldering not my forte either! Its likley to end up the other side of the room in the bin, will leave it to the experts, although about Four years old only out of box last Saturday,

How much too long, and how much modification are you willing to undertake ?

If its just a tiny bit too long, and its because the pins are over-long, then they can be trimmed a little.  But it needs some care to not end up removing the pins from the decoder.    Or, the model could have the socket removed and everything hard-wired.    Either practise will invalidate any warranties.

In terms of control quality for the small motors found in N, there are two outstanding small decoder makers:  Zimo and CT Elektronik. 
Zimo have decent documentation, a warranty service which works within the UK, and a help desk which answers questions in English. 
CT can be difficult to deal with, documentation has gaps, support variable to poor.    What CT have going for them is size, they make by far the smallest decoders available. 

Small six-pin options, which means you don't have to re-wire the loco:
Zimo MX622.  Cheap for a top-end decoder (around £20), and very good.  But you say too big. (14x9x2.5mm)
Zimo  MX617.  Marginally smaller than the MX622, but nearer £30.
Zimo MX616.  Considerably smaller ( 8x8x2.4mm), but nearly twice the price of a MX622 at around £39

CT DCX76.  small  (11 x 7 x 1.3),  around £30
CT DCX77.  really small (5 x 7.5 x 1.8 mm), around £30. 

In all cases they are available with six-pin connections, either directly on the decoder (like the MX622N), or with a plug on the end of wires.   

I wrote an article, its on the 2mm Scale Association website, on how to setup (tune) CT decoders to get the most out of them.  Though some years old, its still valid as an approach. 

There are other small decoders around from other makers.  They don't provide the same quality of control. Some people find them to be OK. 

- Nigel