60's and 70's british sports cars (mostly MGB's) are fairly common conversions.
I don't think you will find a kit specific to the car, but odds are reasonably good that one of the more reputable EV parts sellers will have a design on file for an adapter plate for the transmission.
You can buy kits that aren't specific to a car model, but are intended for certain weight and performance ranges. Such a kit will generally get you all the major components except adapter plate, battery, and battery boxes.
Another technique might be to get the transmission out of a datsun or toyota (pick a commonly swapped model to british vehicles) and find an EV adapter plate for that. You will get a more reliable transmission at the same time. With a big enough motor you could lose the tranny altogether and go direct drive, but that makes the conversion more expensive and limits your options a bit.
Look in the garage section and the austinev "evalbum" (google it) for various examples. I haven't bought a lot of EV parts lately so I can't speak to who the best resellers are for parts. Most of the places I have worked with in the past no longer exist.
As for battery, the best way to go these days is a surplus nissan leaf battery. You will need to rewire it for half the volts and double the AH, for example if going with a 144V Curtis/HPEVS AC motor and controller, common in such conversions.