This is what makes traditional street lanterns so interesting.
Before the internet came along, you had to rely on manufacturers catalogues or actually owning the lanterns in a collection, in order to identify them. Many of the folk on Ukastle are far more knowledgeable than I am (when it comes to recalling model numbers). For those lesser mortals (myself included), I would strongly recommend a visit to Simon Cornwell's website (not that I'm knocking Mr Barford's excellent resource btw).
In some respects, lantern identification can be easiest when you apply basic 'human' personalities to them (the notion of which might alarm some people).
It might indeed sound odd, but I reckon the same philosophy is applied to the design of other 'things' such as cars etc.).
My theory tends to work on the idea that a lantern's design tends to look 'happy', 'neutral' or 'glum'.
Example of 'Happy' lanterns.
1. Thorn Beta Five (all models)
2. Eleco GR100
3. GEC Z9530
4. GEC Z9494
5. Thorn Alpha 8 (original style)
6. Philips Mi26
Examples of 'Neutral' lanterns.
1. Thorn Gamma 6
2. Thorn Alpha 3
3. Eleco GR550
4. GEC Z5590
5. Thorn Alpha 6 (S-C/O version)
6. GEC 'Dioptron'
7. Philips SGS201
Examples of 'Glum' lanterns.
1. Thorn Alpha 1
2. Thorn Alpha 6 (C/O version)
3. GEC Z9480
4. Philips Mi50 (aluminium canopy)
5. Atlas Beta 3
Obviously, the list isn't exhaustive and has no bearing on the 'popularity' of the lantern in a collection. What I have noticed is that most 'glum' lanterns tend to have the lampholder on the 'kerbside', which tends to give them a more 'severe' appearance (compare a 1980s Philips Mi50 with a late Mi26 and I hope you'll see what I mean).
Even the type of bowl can make a difference in its look, ie the Alpha 6 with the cutoff and semi-cutoff variant.
Like I say, this concept might have few supporters, but I have always found it quite an interesting way of identifying lanterns (for the past 40 years).
That said, I have yet to apply this 'logic' to LED lanterns - I think I'll struggle, but I welcome your thoughts.