TCAS only becomes a problem in a very high traffic environment with contra circuits. You will get 1 and 2 alerts on a sunny afternoon in these environments.
There is a huge difference between 270KTAS GS and KIAS. EN 1.1 65.1 clearly states Indicated Airspeed. Some people might call it a grey area, I say they need to reprint their AIP because its black and white.
I would like to know what time of day? How solid was the cloud base? These questions could be taken a long way; perhaps a change in attitude of how VFR pilots operate?