Singapore Airlines and BA(? 747's

I was at Dublin on my Ryanair flights and on the night of Wednesday 9th i saw between 1940 and 2015 a 747 (quite sure it was 747) with a dark blue underbelly land at Dublin. Im thinking it was a BA one and what was it doing there?

Also yesterday (12th) at approximetly 1600 i saw a Singapore Airlines 747 land at Dublin.

Anyone confirm RE: BA and also confirm what was a Singapore Airlines 747 doing there has havent seen that before!