David. Go do one.
In your first post here, you said it was cranking but not starting.
In your second post, you now say, having ignored the suggestions given to you, it does sometimes start. "simple as that" - obviously not, if you don't give us any information to go on. We're trying to help YOU with YOUR problem with only what you give us to go on.
And to then slag us off for our efforts? Thanks, you arrogant tool.
Why do you insist it is in the battery, when its clearly cranking at speed with no trouble? Have you even confirmed whether you have spark or fuel pressure yet? If you don't have a clue, don't piss others off for YOUR shortcomings.