Possible reasons for dry dead  like areas : 

 The conditions of late have changed dramatically with good rainfall drenching the sub soils around the coast. This alone will see lawns repairing on there own. To help your lawn recover quicker the following will help. 

You will be surprised as to how well 'Sir Walter' can recover.

Solution

Remember your 'Sir Walter' will repair it self, depending on how bad it is as to how long it will take, to aid this repair process you can do the following: Just be on the look out for lawn grubs as they like a healthy lawn this time of year, for more info see http://www.daleysturf.com.au/pests-(lawn-grubs).html