The dividend is worked out as follows:
Total debt = £26,500
Monthly contribution = £200pm x 60 = £12,000
IP fees (say £5,000) - not really sure about what these would be and whether the equity would affect the level of fees.
Contribution going to creditors = £12,000 - £5,000 = £7,000.
Therefore, £7,000 / £26,500 = 26.4p in the pound dividend to creditors.
As mentioned, the fees are the only thing that could change, and this would push the dividend up or down.
I'm not sure about the house position, that's one for the experts!
The only point I would make is that MBNA are not one of the more favourable creditors, and as they account for 43% of your debt, you would need them to either vote in favour of your IVA, or not vote at all.