Partner will be bidding in the expectation that you hold values, partly because the opps' auction tends to suggest a relative lack of values (yes, I know that responder could hold a goodish hand with short
♥, which is why I used the word 'suggest' rather than 'show') and partly because it is usually better to bid optimistically rather than pessimistically.
That latter point suggests committing to slam (I'd use 5N to force partner to bid his 6 card suit if 65), but one can have too much of a good thing. The partner first to act under pressure should bid optimistically, his partner should bid pessimistically.
I agree (yet again: this is getting boring) with Justin. Your cards are not a powerful as, for example, a hand with fewer hcp but better distribution both of shape and high cards. Give me Axxx Axx Qxxx Jx and I would happily commit to slam.
BTW, 5
♥ is a cue bid here: you cannot logically hold a suit that you can introduce as trump at the 5-level on this auction. But for me, 5
♥ or 5
♠ should be grand slam tries of some sort: exactly what the distinction is, I do not know. It would be the type of question I would raise in the bar after the game and, with any but a long-term serious partner, promptly forget.
As to 5
♣ rather than 5
♦, there is a 'law' that suggests, paradoxically, that it is sometimes better to play in the weaker trump suit, but I don't think that that law applies here

. So I would bid 5
♦ (aha... I disagree with Justin) but I certainly do not feel strongly about it.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari
2♦ P 2♥ 4NT
P ?