This article from May 2017 (http://www.telegraph.co.uk/football/2017/05/17/southampton-chairman-stresses-saints-stability-admits-claude/) talks about Reed and Semmens (along with Krueger) forming the "club board". And indeed, Companies House shows Semmens and Reed joining 'Southampton Football Club Limited" board soon after (here: https://beta.companieshouse.gov.uk/company/00053301/filing-history), however this recent announcment is for the holding company, i.e. "St Mary's Football Group Limited".
So, I think this is different to the announcement of their appointments last year (to the football club board) but not sure if there's any significance in them also being appointed to the parent company board 6 months or so later. Probably not, but thought it might be worth a mention.