There are only a few "named" Westfield models, the majority of kits (whether home built or factory built) are not specific models in the tin top car sense.
As Stuart said, the nearest you'll get really is more of a general designation than a proper model.
SE - narrow (or original body size), live axle
SEi - as above, but with independent rear suspension
SEW - wide body, (now the only size option) with live axle
SEiW - as above, but with independent rear suspension
Further to that, You may see on cars from the last fifteen years or so, FW SEiW or ZK SEiW, (the FW or ZK may be before or after the rest.) These refer to either the later more rounded style FW bodywork, or the traditional style ZK bodywork.
To throw confusion into the mix, many owners have sort of invented names for their own cars that never really were in use by the factory, some stick, some don't!
Actual factory used model names which meant specific things about the car included:
SEiGHT (V8 car with unique chassis to the V8, at the time)
Speed Sport, a specific spec Zetec engined car, originaly with tuned Dunnel engine and certain factory options from new. (Normally has an id plaque, but these can get lost over time.
Speed Sport Carbon, as above, but with carbon fibre options as standard!
Megablade the three factory motorbike engined cars, with Fireblade, Blackbird or Hayabusa engines and gearboxes.
Megabird
Megabusa
Aerorace, a Zetec powered car with race modified chassis
Mega S2000, Honda S2000 engined car with unique chassis part derived from the Aerorace chassis.
Sport 250, A 2.0 litre Ecoboost engined car used a slightly modified version of the Mega S2000 chassis.
There have been most but these you see most.