Ufortunately, well rather typical of Motability, is they don’t differentiate between petrol mild hybrid and petrol full hybrid under “fuel type” criteria. Fortunately Motaclarity allows you to define fuel type more accurately.
There are several worthy full hybrids to choose, that you haven’t mentioned mitch, such as the Renault Captur & Symbioz, Toyota Yaris, the much improved MG3 & ZS hybrids and even the Juke, that are easily within your budget. Bigger and more expensive but, taking into account the NVP, include the Volvo XC40, Peugeot 300GT, Honda HRV, Qashqai E-Power and Hyundai Kona. The Tucson maybe a little to big for your needs and would likely be a lower specced one with your budget. Anyway the above link shows you all the full hybrids available now.
It may be the case you see a car you really like but, out of budget yet there’s a petrol version within your range that would work out just as cheap to run over 3yrs. Not all hybrids are cheap to run, the xc40 is one example of that.