Appleclec make fantastic quality built-up letters, illuminate etc all in one. http://www.applelec.co.uk
There is also Vince, a regular here on UKSB who i am sure could help – http://www.3d-signs.co.uk
Alternatively, if you download the uksignboards.com mobile app "Signapp" and go to the "Suppliers Index" part of the app you will find a growing list of suppliers all all sorts.
select the following path…
Suppliers Index > Trade Services & Products > Letter Fabrication > 3D Built-up Letters > List of Options here.
$this->BBvideo_pass(‘$8’, ‘$4’, ‘$7’)