I didn't go into that with her, but it seems to have been both. O'Connell's Phoenix Brewery was bought and expanded into, whereas with Sweetman's (now the Iveagh Market) it was just a case of salting the earth: they didn't want the site, but didn't want anyone else to brew on it either. AFAIK Guinness had no involvement at all in the failure, sale and demolition of D'Arcy's Anchor Brewery just down the street from them, now the Oliver Bond flats.