as salamu `alaykum

surah an-nisa verse 23 states:

Prohibited to you (For marriage) are:- Your mothers, daughters, sisters; father's sisters, Mother's sisters; brother's daughters, sister's daughters; foster-mothers (Who gave you suck), foster-sisters; your wives' mothers; your step-daughters under your guardianship, born of your wives to whom ye have gone in,- no prohibition if ye have not gone in;- (Those who have been) wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time, except for what is past; for Allah is Oft-forgiving, Most Merciful;

surah an-nur verse 31 states:

And say to the believing women that they should lower their gaze and guard their modesty; that they should not display their beauty and ornaments except what (must ordinarily) appear thereof; that they should draw their veils over their bosoms and not display their beauty except to their husbands, their fathers, their husband's fathers, their sons, their husbands' sons, their brothers or their brothers' sons, or their sisters' sons, or their women, or the slaves whom their right hands possess, or male servants free of physical needs, or small children who have no sense of the shame of sex; and that they should not strike their feet in order to draw attention to their hidden ornaments. And O ye Believers! turn ye all together towards Allah, that ye may attain Bliss.

in my limited understanding, the verses of nisa lay down the rules regarding who is permissible for marriage, and the rules of mahram are governed by the verses of an-nur.

a scholar in the uk is stating that a woman must wear hijab in front of an uncle (paternal or maternal) i.e. mother's or father's brother - even though he is mahram to her. the reason he gives is because the maternal and paternal uncle is NOT mentioned in the verses of an-nur. it would appear, based on the outward meaning of the above verses that he is correct - because the uncle is not mentioned in surah an-nur verse 31. he also states that this was the opinion of Imam Abu Hanfiah. however, i am sure the four maddhahib permit a woman to remove her hijab in front of her uncle. how is it then, that the ulama deduced the latter opinion, and is the opinion given by this shaykh correct?

furthermore, the tafsir of ibn kathir, the same opinion is quoted in the commentary to the 31st verse of surah an-nur - that the woman must wear hijab in front of her uncle.