There's no mention in either document of the Tanaiste needing to sign off on such a decision, even if in practical terms it's impossible to imagine London pushing ahead with such a move without at least some form of tacit approval from Dublin.
The presence of this agency has been questioned by many, including Regional President of Lambayeque, Yehude Simon who stated that he would "never" allow such an office to be placed in the region without having first sought the approval of the Ministry of Foreign Affairs or the Regional Government itself.