Have you tried maybe just for the boss setting the chain attacks to automatic in the settings, might help you out a bit, you can still do them manually with the option enabled.

I might just do that, thanks.

Firstly, make sure Joseph has Regen cast on him just beforehand. It may seem insignificant, but those little gifts of health really do add up. Secondly, never let either of them go below half health. Ideally you will have realised how important Heal is and pumped points into that, such that you might have managed to get Vitalise by now. That's an awesome spell as it's faster than heal, and affects everyone.

Then, attack the smaller Golems first, if possible try hanging on the edge and luring one off without getting the other two following.

The chain attacks aren't actually very useful in that fight, as the tentacles keep hitting you and screwing them up anyway. The key is to keep on top of the healing.

I'll go back and try to level up as I don't have Vitalise yet.

First time I tried it Fleece died then for some reason two of the smaller golems ran away but I suppose I'll have to kite them so I only fight one at a time as I can't fight all of them, so far I've been fighting all enemies one by one.

I can't remember if it's possible to get it by that point actually. It's early on in the game, you'll need heal to be lvl 8 for Vitalise, which is quite an ask.

One thing that would help you is if you go and do the Crazy Iven quest. Basically his gibberish is telling you to go and look in the big fish that's hanging up. If you go to the platform near him you'll get a fiery sword. This sword will see you through most of the early part of the game (I think the next good one is the Bone sword, or the Sword of Spirits). The problem with it is that it casts fireball, then you need to walk back a bit to be out of the flame radius, but leave the enemy in it. However if you're not getting your chain attacks in, this won't be a problem.

I remember skipping bows and crossbows with Fleece. Leg sweep ( I can't remember the exact name of the move) and backstab are her best abilities.

I figure you've probably figured it out or given up by now, but for future players:

Just buy a book of lightning (from the woman in the northern part of the market district). You can pause the game and cast all five charges at the boss without unpausing. That will get rid of most of its health. Then you can easily defeat it however you like.