£100,000 over 30 years at 4.5% would be £506 a month. That plus the stipulated £25,000 deposit will get you a bungalow or terraced house near me as of about 18 months ago. Rent in my area starts at around £700 for a house outside of town or a single room in town.

So yes, £500 mortgage is possible. Rent being twice the cost of a mortgage for a similar property is fairly common. Banks and landlords being shitheads is guaranteed.