The reality is I can not say for sure where each of the rubber items came from...BUT...not our host here.  (perhaps I should itemize each Mini part purchase - source, date etc.)

Once bought 2 LUCAS coils from a local, long time supplier 10 years ago.  The 1st coil failed after getting us from British Columbia to MMW 2008 in Irvine, then dying on Hwy. 101 in northern CA on the return.  The only miles it did was Vancouver to Irvine to northern CA.  A 40 year old came out of the parts bin to get us home.  Have run Pertronix coils ever since.

Bought that coil from a local supplier and said he should check back up the supply chain.  Sadly no way he could go back to square 1.  Lucas Sport coil #2 still in the packaging...looks exactly like the original Lucas Sports coils...would not trust it as far as I can throw it.

Also bought a new clutch plunger from him...same price as what MM & 7 sell the item for...warned by a friend in OZ, I went to Vancouver Heat Treat for a Rockwell Hardness test 5.5 on one nose, 6.5 on the other...JUNK.  But maybe I would not have noticed for awhile if I trailered the Mini to events or drove it only occasionally.  Problem, I actually drive Minis to/from events.  My $$$$ was refunded.

I have perhaps a slightly different take on this. Did you buy these parts from our host, or some reputable vendor? If so, did you let them know about it? 

If from a reputable vendor, they might provide some remedy for the bad quality parts. Or, at least know to stop stocking those parts due to customer complaints. Not the ideal endgame, but the vendor does have a reputation to protect and likely will stop selling those bad parts.

If from brand X cheapest online vendor, then you get what you pay for.

I don't have a problem with the much reviled Wal-Mart or Harbor Freight because I can see the products in person when I buy them, and in most cases, if they fail, I can return them. But because I can see what I'm getting ahead of time, I usually am not disappointed even if I can't.  No reason to squawk if you know what you're getting into. (and for an amateur hobbyist, Harbor Freight has been a godsend, though I probably still end up wasting the money I saved because I buy stuff from them I don't need... almost everything I've bought from them met or exceeded expectations and did the job I wanted it to do.)

No help here but it says a lot about buying NOS parts, if you can find them.

Same experience here all rubber products for Mini's seem to be crap and do not last.

Installed new track rod ends, new upper arms with grease retainers & new wiggly pin bushes.  Mini rode on a trailer for 12 miles...rubber boots on both track rod ends split around the perimeter, grease retainers all cracking, bushes on lower arms exploding.

The Mini has NOT gone anywhere on its own wheels except up onto & down off the trailer.

Who actually manufactures this crap for sale to Mini owners?  Are they the Walmart trained suppliers in Asian who have needed to find ways to 'lower prices everyday'?