I think the Lufthansa deal must be partnered with Sri Lankan airlines, Lufthansa don't fly Columbo - Goa..
Sri Lankan started flying Columbo - Dabolim at the end of October.
Mon and Sat, 5.45 am leaves Columbo.
Returns from Goa 8.30am.
They had some really cheap promotional deals (Heathrow-Columbo-Dabolim) at the beginning of the season, but unfortunately wouldn't let you take a stop off in Sri Lanka so we passed.
If we could have spent a few nights in Sri Lanka it would have been great, but with the hassle and times it was still easier just to get a direct charter.
(England are playing cricket in Sri Lanka next November/December max13biker, if you're interested in a dual centre holiday...)