With apologies for the late reply. (I've only just seen this question).
The NUJ's 'official' minimum rates are here:
http://www.londonfree...newspapers&page=INDEX
Some actual rates paid are reported here:
http://www.londonfree...esguide/prregr4j.html
Many local newspapers are struggling to survive and consequently have very limited (or non-existent) budgets for freelance contributions. For a 'one-off' piece of the length you suggest I'd probably settle for simply seeing my byline on it, but I'd be looking for a nominal payment if I was a regular contributor. (I hardly ever submit freelance work 'on spec' these days. The payments offered, if anything, are usually less than I was getting 30 years ago!).
If you do get something accepted, you need to know that most journals require you to invoice them after publication. (The fact that they've got your contact details already, and that they agreed the fee, is irrelevant. No invoice means no payment!)
Chris