Link to the BBC Blog...

http://www.bbc.co.uk/blogs/internet/entr...8c71900c4c

From reading the blog it's clear that flash streams are not going to disappear for some time to come (probably years) but it's clear that ultimately MPEG-DASH / HTML5 will become the default delivery mechanism for iplayer.

I know that there are no guarantees with get_iplayer but would be interested to hear from anyone who is well versed with the technical aspects of this.

This is irrelevant to get_iplayer.  Of the formats available for iPlayer programmes, MPEG-DASH is by far the worst for get_iplayer.  It would be more hassle to download and post-process, it would produce files that many people wouldn't be able to play, and those files would be no better quality than what is currently available.   Things will no doubt change over time, but unless and until it looks like it would be the only format available from iPlayer, MPEG-DASH will likely be ignored by get_iplayer.  There is currently no incentive to support it, at least.  MPEG-DASH could be a boon for the BBC because it provides more flexibility for adaptive streaming of iPlayer content (though I don't envy them the work required for cross-browser compatibility), but again, that is irrelevant to get_iplayer.