Large Collage Maker

[velocette]

I'm trying to replace a large and somewhat dated collage I created a 'few' years ago but can't now locate suitable software. I don't need any fancy layouts or formats just a method of placing say 14 high quality photos to be printed locally at 1metre by 800 mm in landscape. I've been able to find an on-line programme called Potocollage.com which allow me to create the collage but the resultant file is far too small at 4000X3000 for my printing requirement. Companies such as Photobox offer collage makers but using their own pre set templates which I don't require. I use Lightroom and, once a year(!) Photoshop. Any suggestions gratefully received.
Peter