Only other proposal (slightly) of note is also in Butetown - @ Waterfront 2000. That little low rise office park just off Tyndall Street.
http://planning.cardiff.gov.uk/online-a ... APR_114536A 2 storey building with around 800 square feet of office accomodation, and 800 square feet of cafe use on ground floor.
This is the second proposal for the area - wasn't there a modest office development also planned?
Looks like the owners want to capitalise on the Enterprise Zone designation, and the nearby Capital Quarter. Trying to appeal to occupiers who want low-cost modern space in a reasonably central destination.