Complex sentence: Although it houses private residences, Highbury Square was due to have a public footpath through it which had drainage issues in 2010 which prevented it from being opened which led to it being called a "gated community" by local councillors.
Split into simpler sentences: Although it houses private residences, Highbury Square was due to have a public footpath through it. Drainage issues in 2010 prevented this footpath from being opened which led to it being called a "gated community" by local councillors.