What was in the dresser's letter to Sid?

Just as Sid is about to go on stage in Sunderland, his dresser, leaving to go to work on the Bond movie, leaves him a letter.

If it was a simple "cheerio and lovely working with you", then it wouldn't be the length it was (pause the film and see).

Might this have been indicative of something more than a working relationship between the two?

Either way, I expect this was fictional - but, assuming so, I can't see what it hoped to achieve.

It just puzzled me a little, that's all.