Check the batteries are both healthy and have charge.
If the steering lock motor has stuck (from being left unused for that period) it would prevent the unlock cycle from completing & therefore not allow the key to turn.
A good indicator is if you can hear an electric motor type noise from down at the steering column when you insert the key, that repeats a couple of times.?
It does sometimes work apparently; I seem to remember someone on here having the issue temporarily resolved by the AA in the same manner.....or did I dream it?