Well Happyjo, there really is nothing you can do yourself apart from killing the odd few that are pestering you. They are most likely living in your loft or behind the fascia board, the only way to get rid of them is to get a Pest Control company to deal with it as the products required are not available over the counter. If you do employ a Pest Control company, make sure you get a price in advance and ensure the treatment is guaranteed. if it is any help, I used to charge �85.00 to treat the loft etc and guarantee my work.
Good luck!!