The Royal Navy would not accept the US and Japan being allowed to convert incomplete Battlecruisers into carriers without being allowed to convert or build similar ships themselves as part of the Washington treaty. Without Furious to convert during WWI they may already have built such a ship to combat the Zeppelin threat, or converted an incomplete Resistance.
A piece of background information.
The 27,000ton limit on individual aircraft carriers in the WNT and the 135,000 ton aircraft carrier tonnage quotas that the British Empire and USA were given were due to what the RN was thinking at the time. That is the RN needed five aircraft carriers and that the optimum displacement was 27,000 tons. 5 x 27,000 tons = 135,000 tons.
By 1924 the plan was to scrap Argus, Eagle, Hermes and Vindictive and build four 16,500 ton carriers (total 66,000 tons) (or was it 17,000 tons = 68,000 tons) which would complete 1928-38. With the 3 converted CBLs that would make 7 aircraft carriers. If there were no Follies to convert it's likely that the plan would be for eight 16,500 ton aircraft carriers.
With no ships to convert it's much more likely that the Treasury and more importantly the Cabinet, Parliament and the voters can be persuaded to pay for new aircraft carriers in the period 1924-34.