Any reason you need to stick to 18FE? this is the perfect energy for the standard .177 pellet, but the .177 HP with the 60cm poly barrel is unbelievably versatile, you can shoot the 10.3g heavy, 13.4g heavy and the 16.2g Beast on the repsective power levels with amazing accuraccy!
I haven't seen that version for sale where I'm located. There are .22cal versions available in the HP.
You can order a .177 HP, which has the same length barrel as the .22 HP, 60cm, VS 45cm on the standard or 18FPE energy you were asking about, the barrel on the HP also being a poly VS standard rifling on the 18FPE gun.
The HP curve gives you 30FPE, you can check out my thread a few months back, almost 400 shots on the low power curve.