Election prediction using my model

The BBC's "Poll of Polls" currently looks like this:

Con: 34%
Lab: 33%
UKIP: 14%
LibDem: 8%
Green: 6%
Other: 5%

I fiddled around a little with my model, and came up with the following:

Defection Con-UKIP - 0.16

Defection Lab-UKIP - 0.11

Loss of votes for Lib when not incumbent - 0.75

Loss of votes for Lib when incumbent - 0.3

Lib transfer votes to green - 0.25

Lib transfer votes to UKIP - 0.1

Lib transfer votes to Labour - 0.3

Lib transfer votes to nationalist - 0.25

BNP transfer votes to UKIP - 0.8

Lib transfer to nationalist that go to labour - 0.5

if no nationalist candidate

Swing Lab/Con/Lib-SNP - 0.35

Swing Lab/Con/Lib-PC - 0.1

Greens standing in 90% - assume all

Defection Lab-Green for new candidate - 0.06

This resulted in the following outcome in terms of percentages and seats:

	Con	Lab	LibDem	SNP	PC	Green	BNP	UKIP
Percentage of vote	33.4%	33.7%	7.7%	4.6%	1.3%	6.2%	0.4%	12.7%
No of seats obtained	274	270	21	59	7	1	0	0

There are flaws in the model, I've spotted errors in the calculations. However, the numbers are satisfyingly close to the percentages that the opinion polls are returning with. I would like to redo the model more accurately, as I said before, but this is an interesting estimate to go with for now.