Sorry but the wobbly thread inserts, the plastic insulating washer that bends when hot, and the difficulty of inserting screws are not the fault of the manufacturer?
These are units that are at best suitable for a trailer, not for a £50K car. Tradition is great but the Morgan was once a vehicle affordable to anyone, now it is hardly the case and something better is required.
I have changed bulbs in hundreds of similar turn signals that are common on motorcycles and I have never had problems like this.