Yes, a Grey Heron. You can see the long legs, the retracted neck and six 'spotlights' on the wings. From another angle, it would look like this:
http://limerick-birderblog.blogs ... nd-grey-heron.html.
The gull indeed looks like a Heuglin's Gull.
Mew Gull is slimmer, with a slender bill and a more rounder head with a friendlier-looking appearance. The upperwing would show a light 'window', caused by paler inner primaries. The upperwing would be much lighter in color too, including lighter greater coverts. See for example
http://www.magikbirds.com/image.asp?title_id=524.
Vega Gull has that pale window as well and I guess would show more dark streaks on the head, neck, flanks and belly. Although immature gulls can be very variable.
The lack of a pale window and the dark greater coverts together with paler and almost whitish head and underparts fit a 2nd CY Heuglin's Gull. The underwing would appear paler too than it does on the picture but maybe that is due to a lack of light.