Yep, someone at the shop said you could do with a good de-twanging, David!
If you decide on a de-twang at some point, they're dead easy to work on and I know you'd be well capable of doing the fettle.
If you're not doing so already, a nice quiet backstop / pellet trap works wonders.....Argos catalogue, concrete / slab enclosure filled with sand, a large cardboard box stuffed tightly with old clothes / rubber mulch will all be good.