Questioning TfL's office costs

The London SE1 website reports on Caroline Pidgeon's question to the Mayor about the cost of the office space TfL is renting in the Palestra building in Southwark:

Caroline Pidgeon: With work underway to look at co-location of Underground and Surface Control centres, are you aware of any lower-cost office space in Greater London than currently proposed at Palestra?
Answer from the Mayor: Given all the factors that need to be taken into consideration for this co-location – including adaptability and suitability of the building to accommodate the control room infrastructure, ease of connection to key railway systems, location in Zone 1, proximity to incident response staff, the availability of a vacant floor, the Surface Transport and Traffic Operations Centre already being located there – I am comfortable that Palestra represents excellent value for money and is the lowest-cost option that meets all the relevant criteria.