Thanks
c-w-s,
mAAine_flyer and
Flaps Down for your insightful info.
Seems like I'd be cutting it quite fine, and with no late second flight with BA on a Sunday as back-up, probably easier to stay downtown, grab a bottle of fizz and watch the sun come up at 10.45am...
I'd skip the Blue Lagoon altogether. The municipal outdoor pools in Reykjavik are much much better. And cheaper. And more hygienic
Good info - thanks. ^