Thanks for the suggestions, Gazman - I had checked the gutter itself, which is manufactured by Hunter and - try as I might, I cannot find anything on any search which identifies this bracket manufactured by them. There is no marking at all on the bracket - not even a mould number.
I am...
I have exactly the same issue(some 2 years after Vintage6 first asked the question) ....did anyone have an answer as my gutter brackets - (which are exactly the same) are also slowly deteriorating ?
Appreciate anyone's help.