Having bought my MOD54 direct from Morgan I got an email with an 'upgrade' option to the new tank insert, which is excellent service.

The new one appears to be injection moulded, so the design can incorporate rounded edges to the crucial bits that may touch the film. Additionally injection moulding allows for a more flexible design and the two central ribs which could cause uneven development with the older version have been removed entirely. The only question in my mind is whether the claws of the new insert hold the film more firmly, but just looking at the pictures it seems at least two out of the three 'niggles' (edges, ribs, claws) have been solved.