Thank you all for your replies. It's useful to hear what 'old pros' have to say and, yes, Neil2, I think that is a good point - we should look beyond the hull and focus on the boat itself. It is so easy to get into the frame of mind that we are being pulled over the table and sold a boat that is not up to scratch. However, having seen many rust buckets on the canals recently, it seems that even the worst hulls do actually float.
Anyway, the Burscough boat turned out to be not what we were looking for - so the search continues!