The sound certainly hasn't been affected Professor Thump - I never actually asked to return them to be honest - just how to repair it or replace the rubber.
To clarify - (as directed in the little manual that came with them, and via the tips from amy on this forum), I've been gripping the body of the connector section when inserting and removing the earphones (the bit that doesn't flex next to the metal end section). When inserting, I moisten the ear gel a little, insert them at an angle while gripping the connector body (not the end or the cable), and then twisting to achieve the seal, which has proven nice and easy (thanks very much).
When removing them, I grasp the same part between forefinger and thumb.
Personally I think the reason for the little tear is that with the bud going quite deep into my ear canal (I'm an ER-4P user and am used to a deeply inserted earphone - my ears are quite 'loose' I suppose in that respect, and if anything I could probably use an even bigger ear gel than you currently offer as standard (I don't know if you do an XL version of the double flanges but I'd buy some).
As a result of the deeply inserted bud, it sits at quite a steep angle, and as a result the end of the connector doesn't appear out of the little 'notch' at the bottom of my ear as shown in dreven's (wonderful) review thread on this forum. Instead, the end sits a small distance inside the cavity, and as a result, the connector is bent back against its natural direction. I've used them for just over a week now, including five workdays sat at my desk with the ultra-comfortable buds inserted for several hours at a time (a privilege formerly reserved for my ER-4Ps, which I guess will now be reserved only for heavy duty noise levels on the train. thus far the images have coped with every noise the world has thrown at them, but occasionally British Rail rolls out the old rolling stock and the train can be quite deafening as a result. I may have to keep the ER-4Ps for those occasions (and I do love them - they're not particularly comfortable and the bass is nowhere near as satisfying as the images, but the foam tips on those really do block out all noise, even when it's a rattly old train, whereas with the images, they are fine for 95% of all situations noise attenuation wyse (although possibly with an XL tip it'd be as good and comfier than the ER-4P for people with 'loose' ear canals), but you still hear the train pulling in and so on - I'm being UBER picky here - the images are easily the best all round earphones I've ever encountered and I want to make sure they last as long as I want them to.
Anyway, I'm not sure if this explains what I mean, but here goes... hopefully it illustrates where i think the pressure on the end of the connector is coming from - I guess when you're listening for around 8 hours a day on these things, it could cause a little tear/split, and you might find it quite a common user comment, notwithstanding the rigour of your stress testing (which I'm sure is comprehensive and exhaustive - I'm not dissing you in any way - just providing some feedback).
To contrast, here's Dreven's picture, which I guess typifies the average image user's ear (with the connector some distance outside the 'notch' at the bottom fo the ear).