My experience of H2O is that they do not do cheap they are a very established broker. If the barge is at St Jean they have a trailer that can pull a boat of this size out of the water for an inspection. With the survey report it should be easy to see if there is any thing obviously wrong. Doubleing is perfectly normal on barges of this age as they were not built originally of more than 5.5mm steel . The Peugeot based engine could be repaired anywhere in France. 50000 is to much however.