The short answer is, you need at least about 80% of the points. TSB’s Smart Grants used to be rated on 100 points (10 questions receiving up to 10 points each, out of the average of grades given by 3 to 5 assessors). For the last few rounds, they reduced the grade per question down to 5, and therefore the total has gone down to 50.
Why 80% (i.e. 80 points or 40 points)? No particular reason, other than objective observation: we haven’t seen a successful grant which had less than 80% of the points, and all the grants we’ve seen with 80% or more of the points succeeded. Bear in mind we’ve only seen Proof of Concept and Development of Prototype grants, and only about 30 of those, but still, that’s enough of a sample size to get a general idea.
So, if you came here looking to find out how close you were to winning the grant (or losing it, if you won), there you go: 80% is the tipping point.