There are good articles in both Which? and Money Which? in the September issues. Of the 2 articles the most information is in Money Which? If you don’t subscribe to Which? then your local library might. Ours does.Or Which? has a web site at www.which.co.uk/hips that covers this subject.
But do try to read Money Which? as it has average prices for HIP leasehold, freehold and gives a fair and balenced view of the industry.