In reply to paul_in_cumbria:
The average grade is calculated taking into account all the grade bands, including HVD, MVS, etc. There are relatively few routes in the UK at those grades, but they (presumably) get equal standing in the calculation. This has the effect of dragging down the average. The trick is not to take much stock in the average grade, but this is easier said than done, and in the case of the hardened UKC logbook aficionado, coming to terms with this blow can take years, and may require professional help.