In the linked piece, the MoD describes the process in which lessons are learned and the Army adapts

https://www.gov.uk/government/news/afghanistan-experience

The British Army has always learnt from experience, as the dramatic changes in uniforms and equipment over the years show. Even the Force that will return from Afghanistan at the end of 2014 looks and operates differently to the one that first deployed to the country in 2001.

And all of this is due to the service’s ability to absorb knowledge gained on the battlefield and adapt its methods accordingly.

The ability to rapidly adapt to changing threats and realities has been shown time and time to be invaluable, the process is embedded and well practiced.

As interesting as this is, and it is very interesting, the Army does not have a problem with learning lessons, it has a problem with forgetting them.