I have just bought a new 2015 model year Motorhome on the new Fiat Ducato chassis. Unfortunately the converter ordered the chassis without ESC and the associated safety options. Is it possible to retro fit some if not all of the options. For eg. TPMS. Hill descent control, etc.

TPMS you could fit as a third party option? There are a lot of good non-OEM TPMS system, also those who can be used with an existing headunit or monitor.

Bought this myself for my own 2015 motorhome:
www . ebay . com/itm/STEELMATE-TP-05E-DIY-WIRELESS-TPMS-TYRE-PRESSURE-MONITOR-SYSTEM-FOR-LCD-DISPLAYS-/181492286483?pt=LH_DefaultDomain_15&hash=item2a41c88413&vxp=mtr