The MG Owners Club has a really good set up for spares and servicing. However, it does not have any link to the MG company new or old - it is predominantly a parts business with a Club/Forum attached.
The best analogy would be if Melvyn Rutter extended his operation and introduced an Owners Club.
I get a lot of my spares through MGOC (I am a member, but you don't have to use them, and there is no preferential pricing for members), although often use other sources as prices for exactly the same branded part can vary between suppliers. We are very well served in the MGB world, but there were almost half a million built so quite a market out there,
The MGOC website is useful, as mentioned above there are parts diagrams on all the pages so you can select the correct part and associated fittings. It would be good if MMC can replicate - Morgan Spares in the US do something similar - I often start my parts search there, look at the pictures/diagrams and then source something similar in the UK. Not forgetting the excellent Morgan History Facebook Group - the best place to access advice and help from people who really know their Morgans.