Compared to the prior "F" class destroyers these had their cruising turbines removed and were a little smaller.
The HMS Grenville was a modified design based on the HMS Faulknor. At the waterline it was 6' shorter. As side fired boilers were installed some internal spaces were changed.
The 4.7"/45 QF Mk IX guns could elevate to 40° because of the use of gun wells.
The HMS Glowworm had prototype pentad PR Mk I tubes installed to increase the torpedo broadside to 10 tubes.