Repair defence to patent infringement

I came into the intellectual property world by way of spare parts and repairs (though in the designs field rather than patents), so Schütz (UK) Ltd v Werit UK Ltd & Anor [2010] EWHC 660 is a treat - if a 50 page judgment can ever really be described as a treat. The goods involved are intermediate bulk containers - big plastic bottles in steel cages for the carriage of bulk liquids. Often these things are single-use, but not surprisingly human ingenuity has devised means of replacing the platic bottles so that at least the metal part can be reused. Ecologically sound, as well. The big question is, does replacing the bottle amount to 'making' a patented product?
Only if there's a valid patent, of course, so the case also has infringement and validity aspects to it. Whether there was an infringement at all depended on the construction of the claims, which is hardly unusual but does mean that the case isn't particularly interesting from that point of view. More to the point was the 'making' question, and the judge (Floyd J, who opened his judgment quoting Plutarch and referring to George Washington's famous axe, with its three new handles and two new heads) held that the important question was whether what was left at the end of the repair what was left embodied the whole inventive concept of the claim. If it did, replacement would not amount to making. He considered that the inventive concept lay entirely in the metal cage, so when the bottle was removed and replaced the inventive concept was, so to speak (my words not his) untouched. And quite right.
There is also discussion about whether the bottle is an essential means of either of the patens infringement of which was claimed: teh judge didn't exactly pas on this, but it was a sideshow and he didn't think it would serve much purpose to decide the pont without having heard a full argument.
There is also a product tie question, raising section 44(3) of the Patents Act:, since repealed and replaced by the Competition Act 1998. The first defendant argued that the claimants sold the goods on terms which obliged the purchaser to buy something other than the patented product - the bottles as well as the cage, in effect. But the judge said this wasn't a tie, just the sale of a kit from whic the desired product could be assembled.