You know, I wonder if the coil has been wired in reverse for a while. Technically, I don't guess a coil and points system would "care" about polarity, the flow could go either way just not as efficiently because you'd lose the advantage of heat in making the spark jump (it would have to go the other way). Perhaps someone with more electrical experience than I can correct me, but I think that is right for a mechanical system. I have no clue how an electronic system would react, but not at all seems likely.
EDIT: Off work and had a few minutes to research this that has been on my mind this afternoon. Found this article, which frankly is probably what I was recalling anyway.
https://mgaguru.com/mgtech/ignition/ig104.htmI'm betting your coil has been wired and plugs firing in reverse with the mechanical distributor and that the electronic distributor won't work that way. New points and/or condensor might solve the problem (if those were the weak link previously), but not necessarily and I'd check polarity whether it does or doesn't.
EDIT2 - I'd also still check for whether you need the ballast ignition coil (as was apparently in when it stopped) or the higher resistance standard coil. I found the following that may be helpful:
Determining Your Coil Type (Ballast vs. Standard)
It is important when buying a replacement coil that the correct type is selected for the vehicle’s ignition system to achieve acceptable life and performance. Lucas ignition systems have often been modified over the years and determining what is required may not be as simple as referring to the owner’s or service manual.
A sight check should be performed first. Some ballasted Lucas ignitions use a ballast resistor wire between the ignition switch and the coil (+) terminal (frequently pink in color). It is also possible that an external ballast resistor may be present instead of this wire. The ballast resistor will typically appear as a small ceramic brick (with wires) mounted in the vicinity of the coil itself and connected between the ignition switch and coil (+). Ballast ignition systems also have a wire between the coil (+) terminal and the starter solenoid. If the car’s electrical system is totally unmolested these visual clues may be enough to identify the ignition coil type installed/needed.
To confirm your needed coil type it is best to make electrical measurements with a volt/ohm meter. Start by performing the test shown in the top coil images measuring the resistance across the coil’s low-tension terminals with all the wires disconnected. Note this resistance value but do NOT presume it correctly identifies the coil needed. Perform the following additional test.
Re-attach the low-tension wires removed to perform the test. Connect the volt meter between the coil’s (+) terminal and chassis ground. Temporarily fit a jumper wire between coil (-) and chassis ground. The jumper wire will insure that current is flowing through the coil and any ballast components during the test. It is necessary for current to be flowing to correctly measure the coil’s operating voltage. With the meter and jumper wire connected, switch on the ignition and observe the meter. If the meter shows battery voltage (nominally 12V), the system is non-ballasted and needs a standard ignition coil. If the meter displays anything between 6V and 9V, a ballast-type ignition coil is required regardless of what type of coil is currently on the vehicle. Standard ignition coils will have a primary resistance close to 3 ohms while ballast ignition coils are typically between 1 ohms and 2 ohms.
Using a standard coil on a ballasted ignition system will result in low spark voltages potentially leading to running problems. Using a ballast-type coil on a standard ignition system (without a ballast resistor) will result in excessive current flowing through the ignition system. This will cause premature wear of the points and potentially lead to reduced coil life.
