Why Dominion expansion would not produce six more Indefatigables

If Canada, South Africa, and India followed Australia and New Zealand, would continuity and cost favour six Indefatigable-class battlecruisers?

No. Britain wanted newer 13.5-inch ships for its own fleet and could transfer existing 12-inch battlecruisers, while each partner faced different strategic needs.

Extending Dominion battlecruiser ownership would not automatically make six additional Indefatigables an attractive programme. The Royal Navy disliked the type's subdivision and internal arrangement and wanted its own new ships to carry 13.5-inch guns. The proposed alternative was to pass existing 12-inch battlecruisers to partner navies while Britain built the Lion generation for itself. Australia and New Zealand also differed strategically from South Africa, which lay on the route between Britain and India if the Mediterranean became unavailable. A threat severe enough to require a battlecruiser there would already draw Royal Navy forces to defend those sea lanes. Canada, India, and South Africa therefore cannot simply be treated as further copies of the Australian and New Zealand purchases. The financing also differed: Britain paid for one Indefatigable, New Zealand for another, and Australia bought the third for its own service.