Hello sammyb, there are distinct differences between BN1 and BN2 transmissions. The first is the position of the gears slected by the gearlever. By this i mean that the BN2 has what we call a "traditional H pattern shift", that is, 1st is across the gate towards the left and up. 2nd is directly below that, 3rd is across the gate away from you the up and 4th is directly below that. Reverse is across the gate towards you almost as if you were going into either 1st or 2nd then across a bit more against the spring loaded detent then down next to 2nd. The BN1 is a combination of back to front and almost opposite, 1st is across the gate AWAY from you and back, 2nd is across the gate TOWARDS you and up and 3rd is directly down from there. Reverse is across the gate AWAY from you the same as for 1st then against the spring loaded detent and down beside 1st from inside the car the gearlever on the BN1 has more bends in it and comes out of the carpet closer to the floor. From the outside look under the car on the drivers side and he BN1 has the bellhousing (clutch housing) and gearbox all in one piece whereas the BN2 has an aluminum bell housing and the gearbox is cast iron but if it is dirty you may not be able to see that. Also from under the car on the same side the actual gearbox casing part of the transmission has an aluminum casting on the side of the housing that the gearlever mounts to, this casting is bolted onto the gearbox casing by about 10-12 bolts but the BN1 has a two piece casting that bolts onto the casing with only about 6 bolts (from memory) You can see the differences from under the hood (bonnet) on the passengers side with a flashlight. Also the front brake drums are wider but they could have been changed, they should roughly be the same width front and rear. This can be measured with your finger through the spokes and touching the rim on the drum. Yes i know it could have had 100/6 drums fitted but we're only trying to help here not hinder. If you have someone close by with a copy of the Emmerson Healey book that will just about nail it down but remember that it would be possible to transfer all the BN2 specific items onto a BN1 and pass it off as a BN2. It's only when you get down to the small chassis details that will tell you what the car is. I can remember seeing 3 BN1 chassis side by side and being able to see the differences so don't feel bad if this car turns out ot be a BN1 as it's still probably worth the money. From the picture it looks as though it's been in a fairly dry storage area. If this is so then unless the car was rusty before it was put into storage then there should be no reason to suspect major rust apart from the usual spots that are easy to see anyway. You should be able to get the car to some place and get it up on a hoist just as a condition of sale to get a better look, that should tell you all you need to know. Keep asking questions there are people who are willing to help you. Just remember there is no such thing as a stupid question, just a stupid person for not having asked in the first place. All the best, BUNDYRUM.