Enjoying your various detailed election threads, but you've got some crazy lingo there.
1. What are "notionals"?
A "notional" result is an estimation of the result in that constituency if tyhe boundaries for the election being contested where in place at the last election. In the UK, this is quite a new science having been done for the Feb 1974, 1983, 1997, 2005 and 2010 general elections/b]
2. What is the "swing", such that, as seems to be the case, the "swing" is from just one party to just one other party, even though there are three significant parties (or more in some areas)?
Swing is the average of change from one party to another. For instance: Con +5% Lab -3% Lib Dem -2% means a Lab to Con swing of 4%, Lab to Lib Dem of 0.5% and Lib Dem to Con of 3.5%. When people say "The Conservatives need a 6.9% swing to win a majority, it means that if 7 in every 100 Lab voters switch to Con, then 116 seats which are currently Lab would be turned into Con seats
Or is that too complex for you?