Hi Simon,
Since there was no licence accompanying the initial delivery of your photographs to the agency as per the commission, a court would try to discern what the parties meant to happen in the context of normal conventions which prevailed in that sector at that time. So for example it can immediately be implied from your acceptance of the commission that you were licensing the agency to use the images, and by extension if you did the shoot in the restaurant or using dishes prepared by them, it can be assumed that you knew the ultimate end user of the images. From these basic assumptions it is hard to say what other terms might be implied, for instance about how the images might be used (press advertising, fliers, promotions, supplied free to illustrate review articles etc) or the term of the licence, as this would really depend on what you were told at the time. Did the agency put the commission in writing, either at the brief stage or during the shoot stage prior to delivery of the images for approval? If so there may be something there from which the possible term of the licence can be implied. But in the absence of anything like that I think a court might well conclude that you and the agency intended the licence to last for as long as the restaurant need the images for - in other words the position which the restaurant is taking at the moment - otherwise a lesser term would have been expressly stipulated.
Another factor which may point towards the expanse of the intended licence could be the amount you were paid for the job and how that relates to the industry rates which applied at the time. So say the 'standard' going rate for the job can be shown to be £300 to include a licence allowing multiple media and an indeterminate period, but you were only paid £150, a court might be persuaded that the lower amount reflected a more restricted licence. We have to assume that the quality of your work was not an issue because the agency accepted the work and the restaurant seems happy to still use the images after 6 years. But that argument would be somewhat hard to support if the agency could show that you accepted other jobs for similar money but where the licence was demonstrably more extensive.
And the other thing to note is that this is a contractual issue between you and the agency and not between you and the restaurant. If you tried to sue the restaurant it could only be for copyright infringement and not breach of contract, and I think they would have a strong case for saying that they believed in good faith that there was an open ended licence which attached to the deal they had with the agency. That would tend to conform to standard business practice for this sort of thing. Indeed if the agency had been operating for some time and weren't as inexperienced as you were at the time, they may well have provided the restaurant with written terms and conditions which covered aspects such as this. And assuming that the court accepted the restaurant's argument, whilst also agreeing with you that the licence had ended, the restaurant would not be liable for infringement since they were not primary infringers, but instead were acting on a false authority provided to them by the agency, meaning that they had no reason to believe the images were infringing copies (see
section 23 of the Copyright Designs and Patents Act 1988).
On balance I think you may need to walk away and chalk this up to experience. From a strictly business point of view it may not be worth your while to pursue it, given that you would probably need some proper legal advice and representation in court if you went down that route - expenses which you cannot reclaim even if you win, assuming this went to the small claims track of the IPEC, and as you say, the court would only consider damages which cover the period after the implied licence
might be found to have ended.
It does make sense and I guess I also thought the same really. Just have to bite the bullet and let this one go 