just wondering if we have any in here

my main stop cock into the house has started leaking , its very tempremental the best of times.. ive tried nipping it up but no joy.. its not a massive leak but its there and pissing me off..

the leak is coming from the tap itself, if that makes sense, its the front of it, looks like a little union

what am i looking at paying for having somebody to come out and sort it for me?

the main tap to turn the water off to the house is on the pavement at the front of the street

thanks gaz