Hi Pete
So where did you live?
We were on the Mitcham Road/KIngsley estate. Our house backed onto the railway line at Waddon Marsh. I lived there from the 70s-90s. Infact, family are still there.
Here are a few pics looking towards the gas works from Waddon Marsh platform and one from near Wandle Park. These are mostly from the web so you may have them yourself already.
http://vakart.org.uk/download/gw00.jpg
http://vakart.org.uk/download/gw1.jpg
http://vakart.org.uk/download/gw2.jpg
http://vakart.org.uk/download/gw3.jpg
http://vakart.org.uk/download/gw5.jpg
http://vakart.org.uk/download/gw7.jpg
http://vakart.org.uk/download/gw8.jpg
http://vakart.org.uk/download/gw10.jpg
http://vakart.org.uk/download/gw11.jpg
http://vakart.org.uk/download/gw12.jpg
The "Britain From Above" site is good for seeing the whole scope of the gasworks. This pic shows Purley Way from bottom left to top right and the gas works enclosed in a roughly triangular block of land.
http://vakart.org.uk/download/gw13.jpg
The white houses that begin at the bottom of the bridge were gas worker cottages. The gasometers were there until the late 70s.
The site was mostly redeveloped in the 80/90s. The main site (where you see all the smoke being generated) was highly toxic and was a massive hindrance to development. This was where town gas was made.
The farthest end of the site would later be used for the more modern plant that was built in the 60/70s. You can see part of that complex in gw7 and gw8 above. That part of the site has only been cleared of the hazardous materials in the last five years and is now a development called New South Quarter.
Lastly, here is the site plan I uploaded last night, overlaid on a modern google map.
http://vakart.org.uk/download/gw14.jpg
And why my interest? Apart from growing up in the shadow of the power station and gasworks, my grandfather worked there and once took me on a tour of the site. It made a lasting impression.
Hope its useful.
Regards
Tim