This house used to have ivy growing just as you describe - a previous owner had become old and infirm and the garden had just got away from her. Do exactly as Nutcutlet has advised. Cut through all the stems as near the base as possible and treat with Roundup stump killer.
The Ivy will then turn brown and the leaves will fall off. You can pull off the fresh growth quite easily, where the adventitious roots have not taken hold, but older stuff you need to leave until it dies and then get someone to attack it gently with a scraper, taking care not to damage the brickwork.
At the same time whoever does that should note whether the ivy has damaged the mortar between the bricks, if so it will need repointing before frost gets in and makes it worse.
It would be a good idea to get a local builder or property maintenance chap to check out your chimney and soffits to make sure the ivy hasn't done damage which will be made worse by winter weather.