Don't know what you were looking at but £800 gets you a 1-bed on the Grassmarket: https://www.zoopla.co.uk/to-rent/details/60126258?utm_source=v1:5bWFDybfWx7C7AGpeagt7mP3PgcqjuqJ&utm_medium=api
It's got electric heating, yes, but definitely within my definition of "decent".