Hey i have at the moment leased a Mobility Scooter from wheelfreedom they are motability Accredited but as i have a motability car i lease a large Scooter from them a TGA Vita S with upgraded battery so it can go 30 miles vs 20.The price is slightly lower than motability and the lease is for three years.Just to let you know you get a brand new product and i have been with them for many years and find them good for service, they are based in Guildford in Surrey and they will come out to you if you want a demo.
It might be worth noting they are london/Surrey centric.