I know that some of your questions have already been answered on the rumours forum but to answer your question about whether all 737s are capable of landing in foggy conditions, you should know the following:
some aeroplanes are equipped to operate to category 1 conditions only (550 m visibility), others to category 2 conditions (300 m visibility), and others to category 3 (a, b, or c) conditions at reducing visibilities less than 200 m.
I believe that Ryanair operate several older Boeing 737-200 series aircraft which are only capable of category 2 operations. They also have some newer 737-800 aircraft which are certainly equipped for category 3 conditions.
My guess is that you started your flight in a - 200, and changed at Stansted airport into a-800 aircraft.
on another point, when Low visibility procedures in operation at an airport ATC are required to slow down the flow of traffic and therefore it is often necessary for aircraft to enter holding patterns waiting for a clearance to commence an approach. It can often be the case that they Pilots do not know how long they must wait a holding pattern before they receive a clearance to continue. We would always like to be able to tell the passengers exactly how long it will be before landing, but sadly, we don't always know ourselves.