"they're purely to keep people in work"
If thats the case how about this.
Option A - Buy 6 armed to the teeth foreign built OPVs/Corvettes for about $300 million.
That leaves $284 million in the pot. Bus the ship yard workers the 45 mins to Rosyth and put them to work on the Carriers. Net result -twice as many OPVs, Carriers delivered early, skilled workforce retained, and money left in the Jar to pay for the Navy s Increased need to fund more Flight deck cocktail parties every weekend.
Option B -Buy 6 armed to the teeth foreign built OPVs/Corvettes for about $300 million. Give each BAE shipworker a mega golden hand shake and tell them to do one. With the remaining $200 million give it to India to pay towards their P8 MPA program. Simples