Nick you're correct about Carltons built at Raleigh Nottingham having W frame numbers.
I may be mistaken but I think Raleigh, sometime during the late 1980s, briefly reintroduced the Carlton name on two machines (not for long though).
This Record Ace is 1980s (I think 1984) - it appears in a number of Raleigh brochures I have in my collection.
With regard to the Lightweight Unit as distinct from the SBDU (as you know I have one of each). My LU bicycle - bought as a complete machine in 1984, is a Corsa. Reynolds 501* throughout (maintubes, stays and forks), Prugnat shortpoint lugs and Gipiemme chromed dropouts. Close clearances no 'guard eyes.
*501 being chrome molybdenum with a little manganese, whereas 531 is Manganese Molybdenum. 501 is double butted.
It has a full Shimano 600 group, my only bike (apart from my MTB) so equipped. With Weinmann rims, a Cinelli"Giro d'Italia"bar and 1a stem with Benotto tape, silver Sedis chain.
Bike is Oyster (pearl white) with white benotto, red cables and a red (faded) Rolls saddle.
Quality bike; lives indoors, has miles under its wheels though.
Owned from new, mint, never restored - spokes could do with renewing though! LU frames have a"WL"frame prefix, and the bicycle (or frameset) cam with a card signed by the builder with a photo of him and the frame number.
I think I've said previously LU bikes are often mistaken for SBDU bikes - frame number is the giveaway but not if it's missing!
That's about all I can think of without trawling through tons of reference material.
I'll post some pics if I can get the b****y things uploaded!
Hope this is of interest.
Cheers, Roadking.
P.S restore the GB!