Check Universal Currency Converter for current exchange rate. Major credit cards widely accepted with retailers allowed to charge extra fee. ATM links to US banks widely available. 9.30 a.m. - 4.30 p.m. Mon thru Fri. Few banks open Sats.
British weather is justly famous.
But if you are expecting heavy, swirling fog - you have been watching too many Sherlock Holmes movies. Roads excellent, but often congested in urban areas. Penalties for drunk driving stiff. Visitors uncomfortable with prospect of left-sided driving can use extensive rail and air transport networks. Pedestrians should look both ways prior to stepping off curbs, as flow of traffic from opposite direction.