I had to read this thread a couple of times because I was reading 110L as being a 110 gallons, so thought you were crazy for using a total of 36 watts of light for that big of a tank. Then I saw you were in the UK and decided you must be talking liters. My bad!!
So I've been in your boat as I'm about 16 or 18 months into my first planted tank. I have had algae problems in the past but think I'm heading in the right direction. Here are some of the tips I picked up with my questions on AA over the last several months:
1. Do 50% water changes weekly, and while fighting algae, maybe twice a week.
2. Keep surface agitation to a minimum. I see bubbles in your pic, and my impression is that aeration can release C02 from your tank.
3. Check the Excel bottle for dosing recommendations and follow it closely.
4. Windows = a problem. Stay away from them as drafts or sunlight can really alter your tank.
5. When you can afford it, look at a new filter and different lighting (T5's).
6. Routine routine routine. Stick with a routine of dosing, water changes, etc. so that when something changes for the better or worse in your tank, you can associate it with what change you made in your routine.
6. Rivercats (on this site) introduced me to PPS-Pro for a fertilizing and tank care methodology. I'm about 6 weeks into it and seeing my plants REALLY showing life I hadn't seen ever before. Check into that.
Anyhow, those are some quick tips. I'm by NO MEANS a pro like some of the folks on here, so take my advice carefully