In terms of income multiples they certainly have relaxed the rules to a startling degree in the past 8/9 years - particularly so in the past 3/4. I worked in one of the major banks 3 years ago, part of my remit was to consider mortgages approved and ensure that they complied with 'supposed' central bank criteria, as it turned out, the central bank did not enforce any of their recommendations at that stage, before I left that job, the first 100% mortgages were on the market (only to a select group of professionals), this went against all recommendations at the time - central bank response - none that I ever heard of.
In terms of affordability, I don't know how that has changed over the years, I've heard rumours that this is better than in the past, but can't comment either way.