I also have an 52 MG-TD.
You can easily change the existing front fender side lamps from a single contact socket to a double contact socket. This will allow flashers on the front without the need for LED lamps. That contact set is available form Abingdon Spares. Part 37-030 $29.95 or Moss 152-600 $26.30 (on sale)
Getting them to flash is another issue.
There is a LUCAS module available. In essence it removes power from the break lights on the side you want to flash and provides flashing power to both the stop lamp filament and the (new) flashing filament on the front fender sidelamps. From Moss its 141-400 $110. You will also need the special time delay switch to flash the lights Moss again 162-400 at $138 and the lever, 150-6-- $8 and the mounting bracket which is an additional $6.
This is the easiest rout to go through a bit expensive. Abingdon has similar items. I did get my time delay switch from the UK even with shipping it was less expensive.
When I rebuilt my TD I used a wiring harness that would accommodate the flashers. If your TD does not have this harness you will need to add a few wires.
If you look at the diagrams in the WSM you will see what additional wiring is needed.
Another route to go is to add a period add-on stalk switch and a set of rear flasher lamps.
That approach is explained here:
[SIZE=-1]https://ttypes.org/ttt2/indicators-for-a-mg-td
This is not "Original" but less expensive and probably better.
In either approach you can get LED lamps that are brighter and functionally fit in the sockets.
A word of caution. If you have positive ground your LED's must be designed for that. They are not universal.
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