Ray
All DEP pilots start on the same paypoint (PP1!), irrespective of previous experience. The 54K you state is incorrect - prior to the recent 2.5% increase, 54K was the Captains PP1 rate. FO's are paid 75% of the captains rate - you do the maths.
From this base paypoint there is an annual increment to be added, which varies according to the fleet you are on (greater for LH than MH, SH). The increments are fixed amounts which I will not advertise, but are between 2-5%. Again, FO's get 75% on the captains increment.
From the above you can surmise what his 5th year basic pay will be.