How strange! There are no details about "HeraldPublicist" on Google. However, a user with the name "HeraldPublicist" has been active on Twitter over the last few weeks. It looks suspiciously like a fake news site.
You appear to have shot yourself in the foot with that source Urmstongran.
This is a quote from Prospect Magazine in 2018 about McDonnell's early days:
"McDonnell and his brother, who became a police chief superintendent, went to the local grammar. After a year he was sent on a church grant to De La Salle College in Ipswich, a Catholic boarding school, to prepare him for the priesthood. “We were the classic Irish Catholic family, which meant one of us was going to be the priest,” he says with a sigh.
The altar boy who had to get up early every morning for Mass didn’t enjoy the experience and doesn’t talk publicly about it, but others have heard him speak of De La Salle in terms of “sado-masochistic Christianity,” a regime that enjoyed “kicking the shit out of you.” McDonnell sticks to: “I did a few years there until I was 15, 16 and basically discovered girlfriends, so celibacy wasn’t going to be an option. I was also into politics.”
www.prospectmagazine.co.uk/magazine/john-mcdonnell-socialist-kevin-maguire-profile
Please note that it is the journalist who refers to the school as "De La Salle", not McDonnell himself.
"Ipswich De La Salle College" is listed in the 1944 edition of "The Catholic Schools of England and Wales", even though it was known as St John's College since its opening in 1937:
archive-uat.catholicherald.co.uk/article/9th-july-1937/14/new-college-at-ipswich-to-be-opened-by-brothers-of
There is still no evidence that McDonnell tried to hide anything, so no grounds for accusing him of hypocrisy.