Or
contact your local IAM who are experienced riders who want to pass on their skill and knowledge to help you enjoy riding whilst being safe. I am doing the course we ride out once a week stop many times for briefings get a coffee halfway and do about 80 miles each session. When you join they send you a copy of the highway code and the advanced bike book which is similar to the Roadcraft book Philthy mentioned. I have had four sessions and its transformed my riding skills (IMHO) I would have described my style before as similar to yours, flat out down the straight and embarrasingly slow around the bends.
www.iam.org.uk The cost has been £85 and each week I contribute £5 towards the observers petrol.
The bikesafe course was fully booked when I enquired and someone suggested I try IAM and I am very pleased that i did. I do not know when I will be ready for the test but at present I am just happy to be learning and improving. I will be happy to answer any questions you might have, if I am able.