Wiping over Socks at Work

Salaams,I have recently started my first job in London, after looking for a long time with quite a lot of difficulty. It's a client-driven company, and so there are always clients coming in and out. I have a few questions to do with my wudhu and another to do with my colleagues.Firstly, with few practicing Muslims, there is no prayer room. There is however a floor of meeting rooms, where I can book a room for 15mins, and read my Salah. I make wudhu in the bathroom/toilets, and my problem is I am not able to wash my feet. This is because of not having anywhere to put my wet feet as I can't change my footwear to slippers and walk around in a professional firm - and also because of the clients that are around and the impression they would get to see me washing my feet (my employers would not be pleased).Therefore I currently do maash and wipe over my socks. My socks are normal cotton ones, which water does come through a little. Is this wudhu acceptable and therefore are my prayers valid? (I follow Shaafi'i fiqh.) Also, on occassions when I am very busy with work for my managers and am short of time, I miss my prayers and do qada when I get home - is this ok?Secondly, there is a big drinking / pub culture here, and especially in my profession of auditing. My colleagues all go to the pub very regularly after work, and have always been understanding to my reasons for not going along. They are generally nice people, and have recently been saying we should all go for dinner since I do not go to the pub. While I do not feel I am missing out on anything by not going to the pub, they are making a gesture to me and trying to arrange an occassional alternative. Now I am quite certain these dinners will involve one or two of them having a few drinks with their meals. Can you comment on the acceptibility of going for a dinner like this? I do not feel I can impose on them and ask them not to drink at all, so is my only option to not go at all?Jazak'Allah Khairan.