Difficult issue for Ashmolean - I'm beginning to discover cracks (5,2,1,7)

I believe the answer is:

horns of a dilemma

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'difficult' is the definition.
I know nothing about this answer so I can't tell whether this works.

'for ashmolean i'm beginning to discover cracks' is the wordplay.
'beginning to' says to take the initial letters.
'cracks' is an anagram indicator (I've seen 'cracked' mean this).
The first letter of 'discover' is 'd'.
'for'+'ashmolean'+'im'+'d'='forashmoleanimd'
'forashmoleanimd' with letters rearranged gives 'HORNS OF A DILEMMA'.

'issue' acts as a link.

Can you help me to learn more?

I've seen this clue in The Independent.

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