If the aerodrome was in the middle of a large plateau, then I would agree. However, it isn't - and to get there means crossing some significant hills to the north. Fine with a BKN018, I certainly agree. But not BKN012.
The point is that the BECMG 0809/0812 FEW040 hasn't happened, neither has the BKN018 - at 1150Z the METAR gave 081150Z 22011KT 9999 BKN015 21/17 Q1017 NOSIG.
You cannot trust such a UK TAF with sufficient assurance to guarantee a VFR trip - whilst you (and I) might be prepared to do so, we always have that insurance policy of an instrument qualification to fall back on if it all turns to worms. But the poor sap with a chocolate teapot rating would have to decide whether to press on and hope that the weather-guessers' incorrect forecast wasn't going to deteriorate still further - or whether to climb up to VMC on top and then hope for a hole.