Yes Malc
I was a bit taken aback at this statement as well, as besides the railway embankment and obviously the nearby parks didn't St Andrews back on to the flats. I understand they have grass there.
As far as the claim to be the first municipal flats, that could be true, were the properties you name in Muntz St built by the Council they might have just been taken over later. The book I quoted mentions properties in Milk St being built in 1898 that is some 27 years before Garrison Lane. I would imagine they were also built privately because I hardly see the authors saying that Garrison Lane was first and then disproving it on the same page.
Phil