Time for a bit of data.
Swanley to Stafford
From Swanley Bridge Marina to Stafford Boat Club is 58 miles. With 41 locks. We managed to do all this in 19 days, of which 8 days of cruising.
Statistics
average cruising per cruising day: 7.25 miles
average cruising per calendar day: 3.05 miles
locks per cruising day: 5.125
cruising every 2.375 day
total engine hours: 41.3