(British amateur, not the American Golden Age film)
The title sequence has 'Made in the UK brings you Garage Girls' or similar followed by pictures of the three girls involved, captioned as Kelly, Sarah and Kim (Kim being older than the other two).
The first scene is set in the repair bay of a garage where two girls - Kelly and Sarah - are discussing the repair of their car with a mechanic. It appears they are on their way out clubbing (I don't know of any garages which open this late myself) and dressed accordingly. He says their fan belt has snapped and he has to send out for one. His waiting room is a tip and they should wait in the back of the car. There is then lesbian action in the back of the car with the mechanic being a peeping tom. He thinks he is unobserved but eventually one of the girls says 'Do you think he's got a hard on?' and the other replies 'There's only one way to find out'. She then opens the door and gives him a blowjob. The girls are in a 69 position at the time; so she is on her back. After a while the girl on top demands to be fucked. Then another bloke arrives with the fan belt, opens the other door and gets a blowjob - to facial, but not very visible. Meanwhile they have changed positions and the other girl is being fucked - he seems to cum inside her. The older woman is the secretary of the garage and she watches the end of this and masturbates and then has a three-way lesbian session with the other two on the bonnet of the car. Camera work is not bad but explicit action is sometimes difficult to see and there is less excuse for this in the on-the-bonnet section of the scene. This is a cut above the standard often seen in amateur videos though. This all lasts about half an hour.
The second scene is a total change of theme and I would suggest that it really shouldn't be in the same video as those who go for this wouldn't like the first half and vice versa. The older woman is seen in thigh boots and stockings and dress lying on a bed talking on the phone to one of the other girls involved in the first scene. Then the mechanic from the first scene (I think) comes in and there is an SM scene where she dominates him, ties him up plays around with a lighted candle etc.