No, I hadn't heard of this until today either.
I think the system has a certain amount to commend it. Each elector would vote for both a local MP and for a party. Basically, it would keep the MP to constituency link, but introduce proportionality by weighting the voting power in Parliament according to the proportion of votes cast for each party.
The problem I have, is that you would still have the problem of any proportional system, that you would almost always have weak coalition government. It would also be possible for the largest single party to be shut out of power by the parties in second and third places. However, I wonder if this can be solved by altering the weightings?
Let us say that the party which finishes first in the popular vote automatically gets to choose the executive. Each party would have an equal chance to achieve this. In Parliament, the Prime Minister and Cabinet would therefore represent the single most popular party, and they would have a collective 5% of the voting power in Parliament in addition to their individual votes as MPs.. They would therefore be more powerful than individual MPs, but would be nowhere near a majority on their own.
The largest party in the popular vote would have 45% of the voting power in Parliament. This would almost certainly include all of the Executive as individual MPs. Assuming the party and Executive are united, they have 50% of the vote and, with the Speaker's casting vote, they can always get their legislation through Parliament. We have strong government. Any division in the largest party could be punished, though, because a single rebel MP would move them below 50%.
The second largest party would have 30% of the voting power in Parliament, and the third largest party would have 15% of the voting power. Combined, they would have equal power to the largest party minus the executive.
The smallest parties (SNP, Plaid Cymru, DUP etc) would have a combined 5% of the voting power in Parliament.
On any 'free' vote, each MP would have equal voting power.