Hi Jack,
in order my preferences would be;
1. Viking
2. Signature
3. Freedom Escape
4. Venus
5. Mustang
Careful on the overall weight of the Viking/Trailer with full fuel and gear etc, it might get close to your 1500kg limit, but other than that it is the standout fishing boat in this group. And also has enough comforts including a fold up rear lounge for the non fishing days. The 115 Evinrude was also the ideal power option when they were new.
Haines Signature are a quality boat but the 530c is not quite as good as the Viking for fishing IMO.
The Freedom is the value for money entry here.
Good luck and good fishing.
Cheers
Dave