Has anyone had experience with seatbelt extensions for old bugs?

I have a '69 and need to get an extension for a front belt, as one of my passengers can't wear it. I only need to go about 2 inches. I was told that you can buy extensions but trying every place in town has shown me that only one company seems to make belt extensions and they are for newer type cars.

I can buy a new seat belt to replace the older one but then have to change the buckle in the middle of the car ('female part') to suit the new belt. Being a beetle with the double buckle in the middle, I then end up buying two new belts for the front of the car.

Alternatively, if I come up with an old set of buckles I may be able to get an extension made up with an old section of belt. Although this is not legal I could get by with it as I have a professional contact that could make it but not certify it. Or, with the buckle set I could send it off, pay a mint, and have the company make a certified extension.

Has anyone else had this drama? Does anyone have an old seatbelt set sitting around that they don't need? Have I missed any alternatives here? Thanks.......

is there any way you could move the seat back another inch or so?

Tried that....even if it worked would have kids feet out the back window! Am hoping to find an easier solution that telling the passenger to walk......

I seen some testing with old seat belts ( no good ) mate makes plane seat belts & has testing station .
all ( older cars ) I have had these are the first thing to go in the bin , you can buy new ones tested & approved