I agree. I am puzzled as to whether MMC have done proper tests on tank/sender/gauge and given out clear advice on the results. We seem to have anecdotal comments from owners and dealers.
The new Plus Four just announced has the usual mods you see to visual elements. My guess is they make assembly of a car simpler and cheaper in some respects. OK the more expensive headlight/indicator combination probably increases unit cost ( borne by the buyer?) but offset by not needing indicators , assembly/fitting during build.
I assume that lessons learnt from the major radiator/brake issues would be built in anyway.