Found on a gate near water, massive thing... i thought it might eat me getting close up.
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You describe this as a 'massive thing'. On that basis, it is perhaps not bromius. The key for Tabanids starts with size:
Large size (wing length 13mm or more)
Moderate size (wing length less than 13 mm)
bromius fits into the moderate category.
They are tricky, especially the massive ones. I don't see enough to advise further.
My Flickr photos...
Having looked back at the photos, i would say this is more T. Bovinus. Would you agree?
Lat/Lng: 52.9009, -1.2294
OS grid ref: SK519339