of course it would count as discrimination, but that wouldn't mean it mightn't happen. there are still law firms where there's no point applying if you went to a catholic school etc.
anyway that is not really my point, as i suspected you did miss it.
all i'm saying is that you would be calling your child a name that would not pass without comment from ANYONE in the west of scotland, bigoted or not. i'm not bigoted in the slightest but if i met someone called Mason i'd say something probably because it would be so unusual.
not something offensive, god knows, more likely something along the lines of 'i bet that's tough going round here'. but in truth they'd probably have heard it from Every Single Person that they'd met that morning and Every Single Person that they would meet that night. it would be unbearable and that's what would make their lives difficult. not religious bigotry itself, but the fact that the name resonates of religious bigotry up here.
also many people would make the assumption that his parents were bigots and that he had been brought up to believe in bigotry. only an INTOLERABLE bigot would name their child that up here. (although i appreciate your boy would have an english accent so that wouldn't necessarily be the assumption.
i can't think of a perfect equivalent but if your surname was Mosely i'd advise against calling your child Oswald for much the same reasons. you could say 'i like the name and i refuse to change it just because of intolerance etc' and you could bring up the nicest lad in the world but people would still raise an eyebrow and comment on it.
anyway, as i say it's unlikely to come up anywhere but the west of scotland so as long as he never wanted to come here i'm sure it wouldn't be a burden. it may be that your rellies have raised an eyebrow but they are reluctant to do more than that. i'm just telling you because you asked for honesty.