Nightman.
You are quite right. However Bell did have a number of problems in writing the history. First of all he was a sailor!!
When he comes to WWII his history is more of an overall perspective of the grand military situation rather than a regimental history, apart from his descriptions of the Dunkirk campaign where he drew on the recent memories of a number of those who had taken part. The feeling amongst most members of the Regiment at the time of publication was of disappointment. Hence the need for people like Lieut Colonel Rex King-Clark to write his two books about the 2nd Manchesters and Kohima and the Burma campaign.
To be fair to Bell, he did not have access to the many official documents which are, even now, still being made available sixty years on.