This sounds like quite a tricky situation. Thinking about it for a while and based on the information that you provided I would have probably executed a G/A even though you weren't able to advise tower of your G/A. You require 210 meters to land according to POH and that is with flaps, you had 180 meters available to the intersection. Based on that you were quite likely to collide with the aircraft departing on the intersecting runway. Despite you being quite low, you were in a pretty clean configuration with only the gear down. With full power you would have had a pretty good climb rate (not knowing the density altitude of your day but I'm assuming) with only the gear causing drag. Based on how I imagine the scenario, I think you would have been well above the departing aircraft. The other thing is, even though you wouldn't have been able to advise tower of your G/A, the controller would have most likely seen what you are doing and (hopefully) instructed the departing traffic to reject the take off.
Like I said, it's tricky and always easier to make a decision when on the ground with plenty of time to spare. I don' blame you for the decision you made. Once you are below the MDA and you are kind of committed to land in your mind, it's hard to overcome that mindset. Especially in split seconds like you had it.
Like the previous poster said, either way an occurrence report should be filed. That definitely was a dangerous situation that could have had a potentially catastrophic outcome. I'm glad that everything worked out well though.