Yes the shares are owned by the 10 local authorities, as they have been in the same proportion since 1986.
But the banks own the company in the sense that they hold large "mortgages". If at any time they foreclose, for example there's a profits or income downturn and MA can't make the payments, then MA is er goosed, to use a technical term.
You might think you own your house, but if you can't meet the payments then you'll be sat on your cases on the pavement before you know it.
Until MA bought EMA and BOH there was no debt and they owned everything. Now, they are very highly geared: they borrowed 100% of the purchase price of EMA and BOH and a further sum, almost as large again, secured against MAN, which until then was more or less debt-free.