I was recently looking through Mathmos' site, and noticed that the warnings about the Heritage bottles not working on the Silver Astros were removed. First I thought this was a mistake, but the FAQ explains:
Although we offer different colours for the Astro and the heritage range, these bottles can now be used interchangeably so the good news is you can now use your Astro bottle on your heritage lamp and vice versa.
So they changed the formula of both lamps to work with the same amount of heat? Either way, I find this really cool as I have been eyeing getting a turquoise/clear bottle, and this is excellent news because it means I don't have to mess with keeping the temperatures down. I thought I'd share this as I did not see any thread about it.