nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqk9fw26axwawt7pmvw2ppgzq5qs8asdx5529xxmxuwenxe289ag6qh228h9 (nprofile…28h9) Ah, no it's not free, it's £20 for pre 2017 vehicles (damn sight better than £195 for the newer one though!)
https://www.gov.uk/guidance/vehicle-tax-for-electric-and-low-emissions-vehicles
(my memory had failed me, I knew they were different prices, just forgot the lower tier)