French real estate investor Corum Butler Asset Management has again added to its Irish investment portfolio and acquired an office block in South Dublin for €33.4 million.  In an off-market transaction, the French investment giant purchased Block F1 at The Campus, Cherrywood. The 69,000 sq ft block has capacity for 600 employees and is currently under a 15-year lease to the payments processor Elavon, with no break clause until 2035.  Elavon is believed to be paying an annual rent of more than €2.2 million and the deal is understood to have an initial net yield of 6.15 per cent for…