This is great. I'd love to see more discussion like this from the ESLs. If I may I like to add just a few comments.
First, Powerlearner, if you competently use the present perfect for underlining the result then I'd say that you've got the toughest parts licked. Past finished actions that have a current relevance and therefore use the present perfect [subject to the speaker's choice] is one of the hardest Pps to grasp.
As everyone noted, the present perfect has within a connotation of 'up to now'. Since 'were living in London' definitely breaks the connection to now, the PP would not be used.
As regards, "This is the first time I tried it", there is nothing grammatically wrong with the sentence, at least for NaE. For BrE, the likelihood.of the present perfect being used is much much greater, but for NaE, there is much more speaker choice involved.
So for examples such as this;
1)He has eaten lunch (= completed as of now, eaten as of now);
2)He ate lunch (= occurred then, ate then)
a NA speaker might choose either. This is where speaker choice, as I mentioned above, comes in to play.
Number 1 could be chosen if the speaker deems the “finished eating” to be relevant/important enough to the present situation, but number 2 could also be used, especially in situations of even social relationship, ie. one where the people are close.
For NaE, we sometimes even use the past simple to ask about experience, for example,
Did you ever ski at Aspen? Did you ever try flyfishing?
(iv)I have lost my pen (= still not found) vs. I lost my pen (= lost, some time in the past, perhaps now found?).
are more representative of BrE. For NaE, the issue is more one of current relevance/importance. At the start of a test, a speaker might well choose “I've lost ...” but again, it's UP TO THE SPEAKER. A speaker might well choose to downplay the significance, maybe because they're afraid to tell the teacher.
I don't believe this distinction can be drawn for BrE, Albertino. The use of the past perfect in this collocation would not, to my mind, be the norm in either BrE or NaE. The past perfect, like the present perfect, is used under certain circumstances, not as a default, if you will.Albertino:
B) "When you were living in London, did you ever try jellied eels"
There might be two possibilities:
(I)If it is BE, then
(i) by using the past tense, it means that the action(tried the jellied eels) is done on a single occasion and completed in the past.
(ii) by using the past perfect, it means that the action is a repetitive, unfinished one (tried the jellied eels on several occasions) from a point of time up to another in the past (while living in London).
Hence, in either case it is correct, depending on what the meaning you want to convey.
(II) If it is AE, then the explanation given above in (A) is also applied to here.
I'm going to say, without great conviction and subject to much rethought, that the past perfect tends to be used from some past point in time back to a further past, not over a period of time that a phrase like, “When you were living in London” entails. [I'm not discounting it outright; as I said more thought is needed]
Before you moved to London, had you ever tried jellied eel?
would be fine, as would “did you ever try ...?”, but the latter, to my mind, would be confined more to casual speech.
Let's not let this drop, folks. I think we're getting close.