Here's a tip from Jim Cheatham in Amelia, VA, USA.
"I have been using LED taillights in my MGA Coupe from the time I finished the restoration in 2017 but have never been happy with the brake/turn signal function because there was not enough difference in light intensity between the running lights and the brake/turn signal lights when the running lights are on. I finally found something that works like I want it to on eBay and it cost me less than $20.00 plus a few hours of my time". For as long as the ling lasts, see:
https://www.ebay.com/itm/313256130559

"The lights are for motorcycles and they come ready to plug into the socket for an 1157 bulb. Because I had already removed the sockets for the 1157 bulbs from my taillight assemblies, I cut the 1157 bases off of the new units, added some extra wire and bullet connectors to connect them directly to the wiring harness. I used two units in each taillight but in order to make two of them fit in each taillight, I had to trim the edges. The attached picture is before I glued the units in place. Not the neatest trim job but you can’t tell when the lenses are on.

The running lights activate the outer ring of the upper unit. The brake/turn signals activate the inner lights of the upper unit and all of the lights in the lower unit. (I connected both hot wires of the lower unit together so it only operates with the brake/turn signal functions.) This setup requires using double bullet connectors for the ground wires and the brake/turn signal wires. I glued the light units in place so they won’t move around while driving. There are 24 LEDs for the running lights and 72 LEDs for the brake/turn signals.

Here’s a brief video of the lights functioning.