power generation from old cooking oil - is it proven? L** p*

On further reading I've gone off it. 

The 8% IRR depends on the loan not being repaid early
The repayments and interest are equal every year, so the interest payments as a %age of principal become very high, so I think it's almost inevitable that the borrower would repay the loan and refinance after a few years (once it's been derisked), leaving us with a rate of return significantly below the headline rate.

This is despite a penalty for early repayment.  I haven't dived in to doing the proper calculation (not having done anything similar for a decade or more) so I stand to be corrected.

I think that the "repayment charge" described on page 7 of the offer document is designed to ensure that the return % is not less than would have applied had the debenture not been repaid early.

I am just wondering whether I have missed an opportunity here. I bought the amount of these debentures that suited me to keep in July and now they are being sold at a 10% premium after less than 4 months. Perhaps next time I will buy some extra with a view to selling. 

I was looking at the Project Trade History which shows actual 'trades' and through October they have ranged from 114% to 110% of purchase price. The overall price to capital ratio is given as 108.9% so the price seems to be going up.  It may be that some investors are hoping to put these debentures into an IF ISA from November but 10% still seems excessive. 

The information about the Abundance ISA does say that they 'expect there will be a way of transferring your existing Debentures into your Abundance ISA. We are working on this at the moment and will update investors when this becomes possible'.  
I have always thought it strange that investors seem to consistently pay premiums for Abundance debentures, even when it seems that some of them would have already returned some of the loan and so one would expect them to be sold for less than the original investment, but I do wonder whether I have misunderstood something. Perhaps once they are paying out they are 'derisked' and seen as a relatively safe investment. 

Yes, as you say 'expect' is not definite, and I was not aware that other platforms have concluded that it would not be possible to place existing p2p investments inside the IF ISA wrapper.  
I have not used the SM for Abundance and there is not much of an explanation as to how it works when some payments have already been made, but your explanation does make sense. I don't know what happens to the interest either - perhaps the buyer just has all the next interest payment but it is still surprising what people pay. On the Ecossol project someone has offered £200 for £175 worth of debenture and the interest, there are 12 days left for more bids and the interest paid out in September 2016.  I find it all surprising but usually very small amounts so no-one is going to make their fortune.