My comments:
1
♠ 3NT
4
♦ 4
♠
5
♦
1
♠ = matter of style, but 1
♠ sure is playable.
3NT = this sort of bid doesn't make much sense playing precision. But ok, it didn't do any harm.
4
♦ = coming from a limited hand, what else can this be but a shape-showing bid? An 11-15 hand is never strong enough to make slam tries unless it is highly shapely. This is especially true since 3NT was also limited. So 4
♦ must logically show at least a very max 55 or a 65 (65 either way). To bid 4
♣ here on grounds that controls should be bid up the line is a technical and logical error. Shape comes first, controls come later.
4
♠ = seeing the wide open clubs and insufficient support for diamonds, this seems a like a sensible action.
5
♦ = to insist on slam despite pard putting off the brakes requires a freak, so this is definitely some 65 or 75. But since anything you bid automatically shows a 65 or better, why should you insist on diamonds? That would have the tendency to negate club control (an inference that now makes sense, because shape was already shown with 4
♦). 5
♦ is more like QTxxx -- AKQxxx xx, whereas 5
♣ is more like the hand you held, and is thus the correct technical bid. By bidding 5
♦ pard fears 2 immediate club losers and must sign-off now.
In short, 5
♦ is a slightly optimistic (though perfectly reasonable) but a moderate technical mistake. The rest of the bidding seems fine. Not that I'd like to be in 6
♠, though