There is only one proper new car: The latest model Toyota Prius on standard 15-inch wheels that qualifies by emitting 70g/k, CO2. Otherwise she has to go for a plug-in hybrid, such as a Mitsubishi Outlander PHEV, or a purely electric car such as a Renault Zoe or a Nissan Leaf or a Volkswagen eUp. The Zoe is reasonably affordable from £17,995 including battery but unfortunately the eUp is £25k. As a further alternative she could go for a Renault Twizy from £6,995 but would need to be able to plug it in somewhere to travel 100 miles. She could also look for a second hand G-Wizz. Or go all out and get a Tesla Model S 70 from £58,300.