Well.. Technically the Sportage is still available.
Just not as FHEV. The MHEV Diesel and Petrol are still available, and the Petrol MHEV can be had as GT Line S too.
That being said, the jump from a Rio to a Sportage is significant, in size as well as economy. Even the FHEVs aren’t “frugal”, they’re just slightly less thirsty than other SUVs of similar size. We managed 41mpg with the GT Line S FHEV, on a route that our current car (1.5 TSI DSG Ateca) usually goes about 45mpg and more.
If the pure petrol variant (or rather, mild hybrid) doesn’t suit you, there is the chance that the new Niro will make it to the scheme at some point this year.
If you’d need other recommendations, if you put down all your requirements i’m sure people will be able to suggest plenty of alternatives (even though they might not your favourite).