Hi Graham.....welcome to the Forums
You have a Karmann Ghia? what a superb car!
There's plenty of choice out there and for the money I would certainly consider a later car with higher miles as Bimmers tend to go on forever once they achieve the higher miles...generally all the issues have been resolved over the years, as long as it has been maintained correctly.
Depends also whether you want Petrol or Diesel and that depends on your regular journeys as I'm sure you want a bigger car (e.g. tourer/estate) and this usually comes with a bigger engine so I would bear this in mind when looking for your new family car.
Let us know how you get on with choosing a Bimmer.
Cheers, Trevor