I have fitted 7" H4 round headlights to my '84 Westy.   They used to be very
common in Europe and the A1 Golf certainly used them as did many other cars.
They are used on many motorcycles too and I would suggest Bosch, Hella, Cibie
or Marschal.
They are marketed in Usa for off-road use only or a special sealed beam
version for US use by Hella and JC Whitney even carry them in a generic Asian
brand which are probably not as good Quality.
Steve