Seat too short!

Have I seen a used WoMo today! Price something (as always) too high! Condition not as described! And yet a purchaseable WoMo! Unfortunately, for my (not too large) size of 180cm the driver’s seat is too far in front and in the seat length too short! It is about a 12 year old Ducato with non-rotable seats! Behind the driver’s seat is a tube frame to hold the upper seat cushion and the headrests of the first seat! Question: Has someone ever converted this tube frame to be able to put the driver’s seat further to the rear? Think of an expandable frame! The conversion could be made, but then the price is even more high! If I look at the prices of about 12-20 years old WoMos, will it be bad for me anyway! A new transporter is offered with around 18 000€! A WoMo with 15 years of age can be made, but then the price is really too high! If I look at the prices of about 12-20 years old WoMos, anyway! A new transporter is offered with about 18 000€! A WoMo with 15 years of age I have to call for a dealer! I have to make a purchase!