In-ear monitors are also a possibility.
Bazza - am I right in thinking that what you are saying here is that the earplugs are blocking out more noise than you want?
If that's the case I'd suggest doing what beemerboy9 has said and make sure you've got the Autocom set up 'just right'.
If you're still not hearing what you want then there are a couple of options. One is the In-ear monitor option.
Pros are that you block out the noise you don't want to hear and pump the noise you do want to hear straight into your ear. This means you don't need to crank up the Autocom volume so high that the sound is distorted.
Cons are that it's not a cheap option (Green Leopard ones with air tubes for durability RRP £110 don't know about UE) and that you have extra cabling all the time (even when you're not using comms, unless you buy a second set of solid plugs but that's more expense)
The other route is to have continuous noise filters added. These allow directional noise from the helmet speakers in while blocking out background noise and are available at different attenuation levels (block out more or less noise)
Pros: no cabling or moving parts. You should be able to add these to your existing plugs (GL RRP £35)
Cons: It's a compromise between sound quality and 'useability' You'll hear less clearly than with in-ear monitors but you don't need to mess around with cables.
Conclusion:
If you want the best sound quality (esp if you listen to a lot of music) or if your hearing is already poor and your budget allows get a set of in ear monitors.
If you want the practicality of plugs without cabling or don't listen to music you may be better off with filters.
But the first thing you should do is make sure you've got the Autocom working properly or you'll spend a lot of money on earplugs you don't need
Hope that helps
Disclaimer I am a Green Leopard agent and so I'm not impartial. However Cumbria isn't my 'patch' so I'm not going to sell you anything
you should also ask what UE's options are and what they would cost. Other earplug manufacturers are available etc etc...