Finally got around to digging this out again and actually got a reasonable amount done.
Finished the section with George in the Congo and completed the first Glastonbury section (though I don't remember ever seeing any windmills around Glastonbury). Then completed the next Nico section revisiting Vernon's appartment.
I found the puzzles fairly easy to solve, the main thing holding me up has been the gameplay. For instance, I know I probably need to use an item to do something so I attempt to use it (4 or 5 times) to no avail. I then wander around making no progress for a bit, go back, do exactly the same thing I did before and this time it works. AFAIK I haven't picked up anything new which would suddenly allow me to use the item, and I haven't tried to use it in a different way from before. Very frustrating. This happened on 2-3 occassions.
Load times continue to be frustrating - particularly when you accidentally move between areas as you have to wait ages for the new area to load, then wait ages for the old area to load as you step back into it. Grrrrrr.
I also wish there was a way to drop out of things like phone messages and item descriptions when accidentally clicking on something I've already checked out. The phone messages don't always reset between sections. I'd say it makes sense to check for new phone messages when returning after making the sort of progress which has indicated I should return to the appartment - so it's really bugging to have to listen to the same phone messages over again (particularly the humourous ones - they might have been mildly entertaining the first time around, but there are limits). If there is a way around this (other than quitting the game) that I just haven't found, please someone let me know!