The London Ultra Low Emissions Zone takes effect from the 8th April this year - next Monday.
Classic and Sports Car have a '9 things you need to know' here: https://www.classicandsportscar.com/fea ... -need-know
TfL have a car-checker here: https://tfl.gov.uk/modes/driving/ultra- ... ur-vehicle
Fortunately for me, my car turns out to be permitted in the zone, despite there being very little information on whether or how kit cars can comply!