Hi Simmo,
Here are my notes on Westerlund 2 from April 2011 with 16" dob. I recall being quite fascinated by it, but didn't know about the interesting properties of its members. Don't seem to have any notes on Westerlund 1.
Thanks for the interesting read.
175X Westerlund 2 is a small bright thin line of resolvable stars packed very closely (this may be NGC 3247) NE-SW at the western end of the large irregular nebula RCW 49 with 20 easily resolved stars. The nebula is shaped like a rectangle topped by triangle pointing S, reminiscent of a child’s drawing of a house. Looks about 5’x7’. UHC filter darkens a segment of the northern edge of the nebula, the eastern section thickens and the triangle becomes dome shaped. “Alex Rodgers, Colin Campbell, and John Whiteoak, working at Australia's Mount Stromlo observatory under the direction of Dutch-American astronomer Bart Bok, published their nebula catalog in 1960. The RCW catalog is largely an expansion of Colin Gum's 1955 catalog.” From “the RCW catalogue” web site
http://galaxymap.org/cgi-bin/rcw.py?s=1