Firstly thanks a whole bunch to all who have responded. I am a late comer to this site, but have loved it since I found it. All information has been useful and it is great to hear others using their Beta's in a similar manner.
I have solved my problems and I thought I would share it with the forum in case it helps others. I am not running an accusump, but perhaps a thought for the near future. I have attached images of the solution I have come up with (I am no welder and this has been done in fabrication shop for me). I went back to the Guy Croft bible, had a good look at things, remeasured everything and came up with the images attached. The baffle plate is 10 mm below than the crank and the pickup chamber has a 10 mm gap underneath. The trap door is located between the pickup area and the windage slots on the top baffle as indicated by the line of spot welds (note the slots are pointing the in the correct direction - make sure of this!). I have added an extra 1.5 L capacity at the rear (something I did earlier with limited success, but have kept in place - helps cooling is how I convince myself it should stay). However, the bad result was due to a large diameter of the bleed holes (I think they were 25 mm). When I hit the brakes hard, the extra oil surged to the front of my sump and up into the crank and out to the catch tank (combined problem of too large bleed hole and because my baffle plate was set too low I think it just splashed up rather than being contained). Now the holes are smaller (6 mm) and under hard brakes extra oil still drains into the oil pickup area, but at a lower rate. The trap door shuts on right hand turns. Well it seems to have done the job and I am happy. The message I have is to measure, measure and remeasure. Following this, take your design and check it against other suggestions from this forum and Guy Crofts manual, then start the job, BUT not before. Thanks again all. If there are further suggestions and assistance please keep it coming. I love this place; keep up the good work and hope this saves someone some pain. Cheers.