Hi Mark
Have a look at the interior shots in this link, you will see that there are spacers under the front seats between the runners and the floor, from memory and its a while ago now so I may be corrected they were wood trimmed in leather to match the car. There was no vertical adjustments on the seats so the spacers may have been made to accommodate the wishes of the first owner.
Geoff.
https://www.gallery-aaldering.com/br...8-saloon-1963/