Hi John, many thanks for the Wheels and Axels, amazing quality and greatly admired here in Germany.
It's amazing how a project comes together and ideas from other "engineers" can be integrated into your own.
I used a "grown out of" (well known Swedish furniture stores) children's high chair for a seat and painted in his favorite colours, added a removable push handle at the back.
He loves it. Many thanks once again, you have made a Grandpa very happy.