Hello Rabbosai,
Thank you for all your helpful messages.
Please can I ask you a question. I had a "mini fall" on day 50. The level of the fall was low because my my filter was stronger than I expected it to be so over the course of an hour the amount and severity of the images I was able to see was limited but definitely wrong. On the one hand I would like to carry on counting on my progress tracker that I had a win so that I don't get discouraged. on the other hand I don't want to mislead myself since I would have fallen far more if I would have been able to. I also don't want to mislead any other GYE members who look at the 90 day chart or forum. Please can you tell me what you think the right thing to do is.
Hatzlocho to everyone!

The fact that you would have fallen far more if not for the filter is not relevant. מחשבה רעה אין הקב”ה מצרפה למעשה. This is what you installed the filter for and that in itself is a win. We're not מלאכים.

Re the images that you did see - there are clear guidelines of what's considered a fall on GYE re the 90 day chart. (I forgot where it says, if anyone knows please share a link). As far as I remember, to be considered a fall in P* it must be pornographic videos or images, not just any untznius sexy picture. To be considered a fall in M* it must be with ejaculation. Anything else is considered a "slip" and can continue counting with a Brachah...

Much Hatzlachah,
Keep going strong...

Thank you so much for taking the time to answer, it's a big help to keep me going. I've now worked out what to do with your help. Wishing everyone continued progress.