Will have a look at my collection of old Airgun World copies, there's a couple of articles about improving the humble Relum, writing by Jim Tyler. Will see if I can find them, and will put it up here.
You could give the H&N FFT a try, not as good as the original Eley Wasp, but much better than the crap they sell these days under the Eley wasp banner
http://www.hn-sport.de/fileadmin/user_upload/pdf/luftgewehrkugeln/produktdatenblaetter/090907_1_FLS_Field_Target_Trophy.22.pdf
Go for the 5.55 mm version
Great video, good to see her getting for that muskrat neck / skull, La coupe de grace as they say. When she gets there it's over for mister or misses Muskrat. Well done.
Who did send you that letter ? public of private person, Write a letter back, accusing them of harassment, because there's no proof of you poaching. They're just trying to intimidate you, so f@ck them !
Would get him a HW30 in .177 caliber or something similar. Good trigger, good consistency, so getting results. Especially when you start shooting it's important hitting the target ..... ! Gun is not to heavy for a youngster.