I’m with Osso, looks like a S1 Duetto/Roundtail to me, although left hand drive not RHD.
The round holes for the side indicators behind the front wheels are a give away to ^this^ originality.. replacement panels all have them in front, as per the later cars. If there were pictures of the radiator support panels and the inside of the bonnet, more could be said.
Not sure what’s so wrong with the welding either, looks like good clean welds on that replacement inner sill, to get to that you have to remove pretty much everything on the outside, including the lower front and rear arches and middle sill, so I’d suggest the sill repairs have actually been done correctly?
The front number plate (black sticker has the 3rd letter blacked out). By way of deduction I’m guessing it’s KNJ 581P (as per the yellow plate in the boot), which comes up as a Red Alfa Romeo. UK people often black out letters in pictures online as it stops people from looking a car up and seeing the annual MOT information, including any advisory’s/mileage.
Looking at the detail in the database (as noted above) states the following:
Vehicle make: ALFA ROMEO
Date of first registration: August 1975
Year of manufacture: 1975
Cylinder capacity (cc): 1962 cc
CO₂Emissions: Not available
Fuel type: PETROL
Euro Status: Not available
Export marker: No
Vehicle status: SORN in place
Vehicle colour: RED
Vehicle type approval: Not available
Wheelplan: 2-AXLE-RIGID BODY
Revenue weight: Not available
Which bears out what the eBay advert says.... “IT WAS IMPORTED INTO GB FROM ITALY IN 1976 WHICH IS WHY IT IS ON A "P-REG" PLATE. IT IS A COMPLETE CAR, ALL PARTS INCLUDED.”
Perhaps the “scratched off” VIN number was issued (made up) by the UK DVLA when it was imported ... a good picture of that before it was destroyed would be handy.
With regards the two different VIN/chassis numbers and rego papers, who knows. HOWEVER, on Willies Duetto register he has a scan of the FUSI chassis and engine serial number ranges (page 10) which lists a 1750 Spider Veloce has the chassis range of 105.57.1410001 - 105.57.1410854.
Which agrees with the paper work as noted 1055700548/F3645
Indeed if the engine number is F3645 (very likely), it also falls in the range and is probably original
What’s not clear to me is what chassis number BillyBob found stamped on the firewall under the paint he scratched off (was this AR2470979 or is that the number scratched off?)
I’m talking about the pictures of the car in the eBay link, NOT the pictures of the 1300Junior posted by Osso to show a roundtail that has been repaired with an S2 front end, no doubt reasonable decades ago as S1 front ends were not reproduced and harder to come buy (OEM only). Those pictures are not related to the UK car in any way but seem to have confused a few people.