I read the guides as to Alderaan for this level of Bioanalysis but the mobs to grind elude me. I've found level 25-28 mobs that I am too senior for and level 40 mobs that I am to junior for.

Can anyone recommend an area of the map to grind the delta please?

If you run the quests in order they are designed to take you through mid 20's to upper 30s. I've been leveling there for the past week. Started at 26, now 35. The quests will lead you through the different areas of the planet with each area going up in level. Remember this is a theme park and was designed to progress in a particular order. The quest chains lead you around the planet. As your level rises, so does the level of quests. Start at the space port and look for any quests you might have missed. (You are doing quest, aren't you? Because that is the designed way to level) Those quests open up the fight against the insect creatures and the internal power struggle among the Houses. From there you'll endup at the mountain pass near the ceneter of the map. It's where the fleet shuttle is. That gives several quests that go from the high 20's into the low 30's. As you decend into the valley you'll find mostly 30's. The glacier valley area is all low to mid 30s. The Elysium quests give you mid 30 Jedi to fight.

IMO If you end up in an area that is way above your level, you should not be there yet. I turn around and look for something I might have missed. This game was design for you to progress in a particular order. I don't get the race to 50 mentality. Then what? I'm more than happy to enjoy the story and wait until more end game content is written and released over the next year.