"buy to let" investment advice

You would have to buy where the rental yield was good, rather than where the potential for capital gain was good. E.g., you can buy a modern flat in the North and tidy it up a bit for 15k and rent it out for 200/month or an annual return of 16%. Any changes in value would be likely to be less than in other parts of the country.

Alternatively you could by a house in the South East for 200k and rent it out for 700/month or an annual return of just 4%. Less rental yield but more exposure to property price fluctuations.

If you think prices could go down you shouldn't invest in property at all, but good property in the North would be the better buy.