I used the following exit nodes below. Please note this is the linux install where the config file resides at /etc/tor/torcc
These nodes were downloaded from torstat.xenobite.eu website. Not sure of exact URL as of now. But you can filter exit nodes by country and just specify the UK ones.
I added the following lines at the bottom and either comment or uncomment the UK or US lines.
# UK exit nodes
exitnodes Alice,anonion,atacama,capoteATWO,ChubZee,DareChPL,dementia,DestroyTerrorismNow,Fenderbender,froschitor,gadg3ts,GZero,IckTor,JimmyGulpRelay,madone,meson
# US exit nodes
#exitnodes 4U2Guess,ac90b671,agent,AldertreeNet,alecto,alphapup,Amunet1,Amunet2,Amunet3,Amunet4,Amunet5,Amunet6,Amunet7,Amunet8,AnAnonymousTorNode,andromeda,AnneOurkey234,Anon,anonomax