Depends what you mean by "acceptable" but it certainly is NOT correct R/T Phraseology as defined in CAP 413 and, I imagine, the ICAO Documents.
Misunderstandings in comunications can be the cause of incidents and surely this is the purpose of having standard R/T procedures. I find it difficult to understand why any professional pilot would deem it acceptable to deviate from standard R/T procedures. Just because some of the herd decide to ignore doesn't mean to say it's right!