I saw that myself, but assumed it was a patent for then new single face rollerblind type attitude indicators, link here, http://patent.ipexl.com/GB/GB838211.html

I think a test piece is beginning to look most plausable.

The last time I was there (Oct 10), there were five Harrier GR.3s (XV753, ‘783, XZ969, XZ996 & ZD667), two T.4s (XW271 & XZ145) and a Sea Harrier (ZD581).
Also residing there, Jaguar (XX845), Dominie T.1 (XS738), Jetstream T.2 (XX479), & Canberra B.(I).6 (WT308) and some helicopters!
I believe more Sea Harriers have moved across since.

By the way, this site http://www.demobbed.org.uk/locations.php?location=2089 Demobbed is very good for lists of aircraft residing at specific places, with pictures as well, search either by location or aircraft type.

Ah Pagen, that was me wild guessing! I bought something that ‘looked’ like a Sea Vixen AI for my slowly expanding project. It’s a 6A/6582 so wrong then?

One of these then, http://www.ebay.co.uk/itm/Attitude-indicator-Artificial-Horizon-SeaVixen-Scimitar-/130534532820, not Vixen, wrong scale marks etc, maybe early Lightning or Bucc, or even Scimitar!
ASI is a MK.15 6A/5572,up to 700 knots ind.

I have a smashed face Att Ind if you want it.

Could it be for the back seat of a training aircraft? What did the rear cockpit of a Wyvern look like?

The only training version of the Wyvern (T.3) crashed in 1950, I would think as in most British training aircraft that both cockpits would have the same standard artificial horizon.

What we do know,
6A/NIV, an instrument intended for flying, NIV Not In Vocabulary, ie unclassified by the stores ref system.
56 date
Made by Kelvin and Hughes
FAA tag
Eagle, possibly serviced, used, stored on HMS Eagle
To or at Strathallan, 1977.

Suggestions,
LSO aid
Catapult aid
Rear cabin of fixed or rotary wing repeater instrument
Simulator control pitch instrument

What is interesting is that it is called an ‘attitude Indicator’ at a time when ‘artificial Horizon’ was in British use.

I mean a deck aid for the LSO on the deck itself, not in the aircraft.

Personally I’m convinced this is not for a main (ie the pilots) panel, a repeater in a crewman cabin maybe. Ship landing aid, ie for last minute flight deck pitch check, or sim I can understand.

The Gannet AEW certainly doesn’t have pitch info in the rear cabin, can’t see why the Skyraider AEW would particularly, that’s not to say it didn’t though!
Does anyone know the ref no’s for Douglas and Skyraider? They don’t appear on that parts list link.

The horizon ind is marked around the circumference in the standard British instrument manner.
Guessing ‘OFF’ is indicating whether the instrument is powered up.

Moggy, I think FoxVC10 means possibily fitted as a repeater in the Skyraider rear cabin of the British AEW.1 variant.
I like the Skyraider theory (right date, & ship-Eagle, etc), however I’m not totally convinced that is what it’s for.
6A is definitely aircraft intsrument intended, sims/trainers generally use another ref, though 6As can be used on them.
As Chris says, intriguing item!

I might have to grow my, sorry, some hair for that!:D