No. He is the best we have had for many a year , but a Grand Slam winner?..No. I so hope I am wrong. Ranked 4 means one thing...an expectation to exit at the semis, if he is lucky.Queens ....unforced errors beyond belief.Yes, he has beaten players higher in ranking, but not when it matters. The titles he has won are minor titles, and mean little.
No British Grand Slam in my lifetime, and in most of yours too.
Having said all that I shall still be shouting for him right up to when he loses , which I predict will be the quarter finals if he is lucky.