All other aspects of the process were adhered to carefully. If there was anything amiss I'd have expected to see any blemishes to appear below the outer gelcoat surface so was puzzled by the surface imperfections

Warren - An interesting point regarding the acetone as I'm sure that one of Matt's tutorial videos shows him using it on the Fiat bonnet infusion. It does feel kind of logical, though, that this might have had a part to play in weaking the gelcoat surface, so I'll likely avoid it now.