I would talk to Wiillans (01327 857788) who are very helpful, and will adjust the lengths of the loops to your requirements, so that the adjusting buckle is in the right place. They also do "Top Hat" fixings. I had a similar issue when looking for belts in 2020, and they sorted me out. Their belts are expensive but great quality. They send out a Spec Sheet for you to complete. On the "Direction of Lap Strap Adjustment" part it is dimension C you need to look at. If you PM me, I'll send you a copy of the sheet I completed.