So, some predictions for the results:-
Conservatives 295
Labour 265
SNP 35
LibDems 30
Plaid 4
UKIP 2
Green 1
NI parties 18
I think most gains for Labour will be London (eg Hendon, Brent Central, Enfield North and Croydon Central) and the Mets, as people are more used to Labour representation there. A notable case in point is West Yorkshire (Leeds NW, Pudsey, Bradford East, Bradford West, Calder Valley, Dewsbury, and maybe Elmet & Rothwell and Keighley). I doubt they will win many other "Middle England" seats that were theirs in 1997/2001/05 but Tory in 1992 & 2010. So, places like Hastings, Harlow, Worcester and Chester seem likely to remain Tory. Seats that were Tory in 1992 but Labour in 2010, such as Exeter and Harrow West, are likely to remain Labour. Seats that were Labour in 1992 and Tory in 2010, such as Warwickshire North and Pendle, could also be easy gains for Labour.
I think the LibDems will lose all seats they gained from Labour in 2005/10, and a few to the Tories which were recent gains or where they have done well in local elections (such as Eastbourne, Wells and Sutton). They could face wipe-out in Wales, losing Brecon & Radnor to the Tories, Cardiff Central to Labour and Ceredigion to Plaid Cymru. In Scotland they will hold at least Orkney & Shetland and probably also Charles Kennedy's seat and the Borders seat of Michael Moore. They seem certain to lose Gordon and Inverness, and regrettably also East Dunbartonshire. Despite the London losses I have predicted, I think Simon Hughes and Vince Cable are safe in Bermondsey and Twickenham.
The 2 seats I predict for UKIP are Clacton and Thanet South.