CJB... gotta say you had me worried as to what I might see when you mentioned endoscope pics (-:
Taking the engine out to replace the alternator, that is Ferrari Dino stuff, even Morgan will hopefully have set things up better than that..?
Was out and under and had a look. MY alt mounting bracket is a three point fixing as suspected. two which can easily be seen from above and to get at the bottom one seems simple enough from underneath the car, I suspect the bolts will be short enough to remove relatively easily, might be best to check what spanners YOU need to complete the job as on my car there are two different sizes holding the bracket the one nearest the wing is of a smaller size and not a good fit on either my imperial or metric spanners... circa 13mm or 1/2" though the other two take a 14mm ring spanner well.
Word of warning be sure to disconnect the battery before trying out the spanner sizes as it looks like it could be all too simple to short between the alternator battery connection and the spanner which you are attaching to the engine which is well EARTHED.
As for getting it out with the bracket attached... Perhaps removing the oil filter may improve manipulation of the assembly.. just dunno..
Best of luck with it CJB, please let us know how you get on..