really, do them yourself as Nickc suggests, its a piece of cake and will take all of 10mins for each end..surely you can spare that?
learning to spanner and the achievement from doing a good job is all part of MTBing for me and it helps on trailside bodges!!
if you really can’t be bothered then surely your LBS could do it for you? shouldn’t cost more than £10 an end but TBH it’ll take more time to drive them there than to do it yourself…