Look forward to seeing the pics Eddie.
I did think on about your filter issue, sadly I have no idea! I even had a quick google search of the product for any problems with it, but couldn’t see anything.

Anyone ever had an issue where their ND filter makes the image blurry? In Iceland just now and discovered that my Firecrest 4 stop (1.2) ND does this. If I set up on a tripod and manually focus on a subject, when I then add the filter it’s blurry. I then can’t achieve focus with the filter attached. Filter is clean and the 10 stop, CPL and grad filters are all fine. Just the 4 stop. It’s the 100x100 glass ones I’m using and it was the Elia Locardi kit.
Was at an epic waterfall yesterday and realised afterwards that all my shots where I used the 4 stop were out of focus. After a bit of testing I realised it’s the filter itself. Luckily I was only 10 mins drive away and managed to go back and retake the shots without the filter but I’m now without a 4 stop and the 10 stop is too strong for waterfalls. Very frustrating.
I’ve emailed the company to see what they say but don’t hold out much hope as I bought it in 2021 (just hadn’t really used the 4 stop much since). I initially thought I had just missed focus on the few shots I had taken with it but it’s 100% the filter. Thought it might be greasy but I’ve cleaned it with lens cleaner and it’s still the same.