Thanks for that- but the rear lights in the picture are quite unlike mine. There is no chrome strip. I did try to attach both pictures but the right oner never went so I will try again. It is the bottom section that is different. Interesting about Alpha- I will research this. Healey was focussed on Chassis and plaigerised many parts from other manufacturers. So the steering box on his cars (Silverstones etc) came from a manufacturer of electric milk delivery vehicles (we call then floats) that was next door. They never did left hand drive so I think the steering box on the Nash Healey is Jaguar XK120.The Nash Healey Club has much to gain by tracking down parts that are common to other cars. I am working on this but it needs a concerted effort in the UK , US and Italy to do this justice.

Ok I have done some more research. The light unit was made in the UK and it is a Lucas 523 type lamp.You are absolutely right, the only other car I have found with a Lucas5 523 lamp and the identical light bezel with the chrome strip across as on my car is an Alpha Guillietta Spider which was also bodied by Pinin Farina!! I noticed in the picture of an Alpha that the lights were the other way up so I checked mine and sure enough they were upside down! I now know that the left hand lamp which has the manufacturer as YAK is wrong. The 523 lamp unit with a variety of different lenses and without the cross strip was used on :-
-Other Alpha Guillettas apart from the Spyder
-Fiat Zegato 750
-Nash Metropolitan 1954-56
-Austin Metropolitan 1954-56
I attach relevant extracts from the Lucas catalogue which quotes all the part numbers. Got there in the end!!

I thought it may be helpful to other members if I summarised my conclusions on Nash Healey rear light units and lenses after extensive contributions from many members on the MOL Forum to whom I am most grateful
Plinth & Bezels:
The rear light units, although not necessarily Lucas items (mine have no manufacturer name on them!!) are identical to the Lucas L523 unit as used on the early Nash Metropolitans except for the fact that the chrome bezel that holds the lens to the plinth has a cross strap that goes over the middle of the lens and through which in the middle there is a bolt that fixes the bezel and lens to the plinth. It would be perfectly possible to modify the Metropolitan bezel by fabricating and welding or brazing the cross strap to the bezel. I have seen reproduction bezels in plastic being advertised for Metropolitans – these do not look right and unless you can physically inspect them I suggest you steer clear.
Lenses:
This is not so easy!! There appear to be three types, all of which fit the plinth and bezel:-

Nash Metropolitan – These have Lucas Script on them and if that is put the right way up the lens has a flat plinth at the top of the lens that goes from one side to the other.

Rambler – These have the script on them NAK and they have a small circular flat reflex that is cast into the centre of the lens at the bottom. This is cast in reflex is in the flat plane to the lens. In other words when mounted on the sloping surface on the Nash Healey, this reflex will not be at 90 degrees to the ground.

Nash Healey- These lenses have the script NAG and include a separate small reflex with a chrome surround that is bolted to a plinth cast into the lens at an angle so that when mounted on the car the reflex is at 90 degrees to the ground. These lenses and the reflex have been reproduced by Patrick & Len McGrady to a very high standard. (See the Cranberry Run construction web site).
If you are looking for total originality then the lenses to go for are the ones made by Cranberry Run. There was some debate about whether the reflex goes at the top or the bottom of the plinth when mounted. The period pictures I have seen show them at the bottom, but I understand they are shown in the manual at the top. The general consensus was they could be either way up, so it’s a matter of personal choice. The other lenses are a cheaper alternative that come up on e-bay from time to time and look just fine. In theory, if you could find a small enough reflex with a chrome surround, you could drill the lens and bolt a reflex to it although it will not be at 90 degrees to the ground. I will be getting a set from the McGradys but will only put them on the car for showing. For everyday use I will put the Metropolitan lenses on the car.
Hope this helps other owners
Paddy Greenwood