newfoundland.jpg

Reliability graph produced by ACE-HF
This shows that to work the Newfoundland-based stations from within the UK, 40m (7 MHz)
is probably your best bet after dark and in the early morning/late afternoon
20m (14 MHz) is a possibility at about 1000 UTC and then after 1600 UTC,
but both appear marginal.
Note the possible 10MHz openings - I have never heard IMD
stations on 30m myself.