Q1. How to distinguish between past participles used as adjectives and past participles that have a passive meaning?
Past participles that have a passive meaning have an explicit or implicit agent.
- She is admired by everyone who knows her (explicit).
- Your help is appreciated (implicit, by me).
- The price of petrol has been reduced (implicit, by the oil company).
Such past participles are typically not modified by very, but by very much or an alternative adverb:
- She is greatly admired. (?She is very admired.)
- Your help is very much appreciated. (?Your help is very appreciated.)
- The price of petrol has been significantly reduced. (?The price of petrol has been very reduced.)
Past participles used as adjectives very often describe mental or emotional states, and therefore have a person or animal as their subject. There is no explicit agent, and often not even an implicit one. Such past participles are typically modified by very, not by very much.
- I'm very bored. (?I'm very much bored.)
- John's been very depressed for several days. (?John's been very much depressed for several days.)
- She looked very disappointed. (?She looked very much disappointed.)
Q2. Which adjectives to use with very and which adjectives to use with very much.
As noted in the section above, past participle adjectives that describe mental states are generally modified by very, not very much. Most other adjectives are also modified by very alone. However, there are some common exceptions. For example, adjectives that describe extreme qualities are not usually modified by either very or very much (?very enormous, ?very much wonderful). There is another group of adjectives that needs a different modifier than very (fast asleep, wide awake, far apart, well known, etc.)
Q3. "This looks very like what we had at our shooting party in November." Is this sentence is really correct?
A short answer: yes, This nGram shows is very much like to be more common currently than is very like, but before 1940 the reverse was the case.
In answer to your supplemental question (How to determine which form to use?), my recommendation would be to invest in a good grammar of English usage* to learn about general patterns, and run an nGram as above on specific instances (or do a simple Google search on the two phrases: for example "is very like" gets 411,000 hits, while "is very much like" gets 36 million - so it is clear which is the preferred form).
*The two books I consulted in preparing this answer were Swan's Practical English Usage and Collins Cobuild English Usage.
Best Answer
Your suspicion is correct. I've checked the following dictionaries:
American Heritage Dictionary
Oxford Living Dictionaries
Collins Dictionary
Merriam-Webster Dictionary
Random House Unabridged
Random House Kernerman Webster's College Dictionary
And not one of them attests to your first quotation example being correct, but instead your second one as being correct.
Generally the definition is something like:
However, note that inversions of this kind tend to naturally drift among people and time periods. For example this is the usage note from American Heritage Dictionary for the word "comprise":
This note is a good example of how the acceptability of word usage changes over time, and I'm not sure if "consist" is undergoing the same sort of drift.
Another and even more contentious example is "substitute" where strictly speaking the "substitute" is the replacement supposed to take the place of the thing removed, however it's extremely common for it to be used the other way around. The dictionary usage panel generally disapproves of the 'incorrect' use. However the panel is more accepting of its use in a sports context, where it's very common for one player to be substituted by another. The thing is that language naturally evolves whether we like it or not.
If you're interested in the "substitute" controversy, here is the link to the usage note.
Substitute