I simply cant understand why the Okehampton lobby keep quoting £3bn for the cut off options. The report quotes £1.6bn for option C4 and there should be plenty of scope to reduce that.
In the same way that there should be plenty of scope to reduce the £0.875m for the route via Okehampton.
Option C5 is cheaper still than C4 and is only £1.5bn. However given the main advantage of the avoiding lines is that they porvide time savings, yet none of them provide more than 6 minutes of time saving.
Also the report lists (at table 9) how resilient the options are, yet C5 "Avoids a limited proportion of storm and flood risk" and C4 "Avoids a moderate proportion of storm and flood risk".
An analysis of reasons for travel on the SW routes might be interesting (including road and air share).