That's perhaps my theory also. Less postcodes in valid areas, so more funds towards those harder to reach locations?
We have £7k vouchers here in Kent (although I was advised the funds were running low) but as you can imagine, it only takes a small handful of addresses to reach the target compared with the lowly £1500 vouchers in 30Mbps+ areas.
We reached £84,500 with 14 homes + 2 business (58 possible addresses but many are 40Mbps+) thanks to the higher value vouchers. Our target was £58k. The project would not be viable with just the £1500 per household.
I'd just noted we're at the same stage - i replied back to the guy who sent this email yesterday, very helpful, who informed me our's was still waiting for the DCMS to green light it, and they had been quiet for sometime, so it sounds like it's classic government holding us both up!
We've got a mixture of £3500 SME vouchers, £7k Sub 30mpbs vouchers and some £1.5k vouchers and our target was £59k.