tommy
The last CAA figures available for the CWL-PIK-CWL route are those for September 2004 when 3562 pax used the route, an average load of 34.
The previous September (2003), when baby were using their own 737 aircraft, 6759 pax used the route. Bearing in mind the relative sizes of the Air Wales and baby a/c, the average load on the baby 737 would have been considerably lower than the Air Wales ATR 42 in percentage terms - in fact that month the baby 737s would have been barely 50% full on average.
The last full month baby operated into GLA from CWL was June 2003 when 8653 passengers used the route - an average load of around 60% on baby's 733s.
In case this was a freak month I also looked at March 2003 for CWL-GLA-CWL and 8144 passengers used the route that month, an average load of just under 60%.
In terms of percentage average loads we can perhaps see why baby have opted for the smaller Air Wales a/c and also for the apparently lower costs of operating into PIK rather than GLA.
None of this makes any sense when one considers the airport 'along the road' (as you put it) seems to convey 26,000-28,000 passengers every month on their GLA route, with both easyJet and BACx on the route.
Finally, we have only been talking about passenger numbers and loads. Of course, the thing that airlines are interested in is yields and we cannot know what they are as outsiders from the companies concerned.