I have found online material that indicates
the Royal Navy could have ended WWI with
fifteen Queen Elizabeth class BB's.
In 1913, the Canadian Govt. was asked to
fund 3 additional QE's, but the Canadian
parliament voted it down.
The R class BB's were supposed to be
repeat QE's, but the Admiralty committee
overseeing ship construction got nervous
about maintaining oil supplies in wartime,
so the design was changed to coal-fired
boilers. The R class was shorter, less
hydrodynamic, and underpowered, which
reduced their speed. To keep their speed
from being too low, they were given less
armour than the QE's.
Renown & Repulse were supposed to be
R class BB's, but Adm. Fisher had returned to
the Admiralty, and wanted more BC's, so they
were built as such.
So, if these decisions had gone the other
way, there would have been 8 QE's and 7
R class BB's, which would have been identical
to the QE's. By the time of WWII, the RN could
have had 2 Warspites, 2 Queen Elizabeths, and
2 Valiants, in terms of updated BB's, plus the
other 9 ships would have been equal to Barham