Thank you for all the great comments
ProDave - It is a voluntary agreement, and I have so far maintained the CIL payments are "unaccepted", but I have been told they are non negotiable. There are some other improvements the project provides in terms of footpaths/renovating canal/tow path and similar which we are still hoping to use to extract some lee way. CIL was only introduced here last summer. Providing the land to broaden the road/bridge "benefits" Surrey County Council, the CIL and PP are via Waverley Borough Council - so the exchange is asynchronous. The new bridge is being funded by section 106 acquired from several larger housing developments in the area, but it can't proceed without my strip of land, (2m x 50m).
If we don't resolve the CIL issue two outcomes are possible - they try to CP the land, or scrap the idea of 2 lanes and install traffic lights. All parties strongly agree a new bridge is the best way forward.
CIL would be about £100k per house, hoping the exempt the first house thru self build, and maybe sell the second plot with DPP
Simon Brooke - Good point, I was thinking the CGT would be from when I bought the house to selling (20 years), not for the mothball duration (couple of years). You are right the CGT would not be too great.
PeterW - YES, primary house is solely in my name, the new house could be in wife's name - if it is that easy to apply CIL/CGT to each of us individually, that should work....I Think we'd end up paying council tax on both in any scenario, not sure if the full rate is applicable on an empty house. Will factor this into the negotiations. Newhome's post may thwart this idea...
I know myself and wife can't have different primary residences (divorcing her to save tax seems a little heartless), and I suppose to qualify for CIL, living in the house wouldn't be enough, it would have to be legally my/our primary residence ?
Stewpot - I need to read up on CGT, the sums will be more complicated. The house/plot cost £550k twenty years ago, and will have gone up in value to about 800k now, but by the time being sold will have gone down again as it has lost about an acre of land (for the two new dwellings) and it will be nearer a faster/noiser road. But you're right the CGT should not be too much, maybe I am focusing too much on it...
The project is still going through planning, but the expectation is the new houses would not be dwellable (legally) until the bridge is finished (or after a pre-agreed duration if the bridge is delayed/cancelled), but this might be negotiable, as the bridge building would be very near the existing house and access could be impacted. Certainly it would be easier to build the bridge without having to provide us a safe route through the site to our house.
Am I right in assuming if I build one (or 2) houses on existing house's curtilage, there is no CGT on the new houses....? This CGT would be significant.