Speak to Motability. They allowed my to change after 14 months because my son (the DLA recipient) had to have a much bigger wheelchair which barely fitted into the boot.
There is no time scale regarding this. If your needs change dramatically, then just get in touch with Motability customer service.
You may find this useful to read Motability If things change
Joss
Current car: BMW X2 sDrive 20i M Sport 5dr Step Auto In metallic Portimão Blue. 04:10:2025
Previous car:Peugeot 308 GT Premium 1.2 Pure tech Petrol.