I am new to traditional heli and have been having trouble getting Servo Reverse and trims to work in ether the GUI or the full parameter list for Traditional Heli V3.4.3, When I loaded 3.3.3 everything works as expected. Is this a problem or am I doing something stupid.
AFAIK there should be no change in Servo Reverse or trims from 3.3.3 to 3.4.3 or 3.4.4 but you are not alone
Usually you should set the trims on your TX to zero (as with almost any other FBL-unit) and use the reverse function of your TX to get the correct stick movements in Radio Calibration.
Standard mistake is wrong cyclic pitch (elevator) movement. Assuming a standard mode 2 setup the green bars should follow your sticks, left and right is obvious, ‘Throttle’(=collective pitch) is intuitive (for up the PWM numbers increase) but for elevator it is kind of counter intuitive for most pilots, as the green bar moves ‘in the wrong direction’, nose up gives higher PWM numbers and nose down lower PWM numbers.
In ‘Heli Setup’ you do the trim and servo reversing (H_xxxx parameters). As with almost any other FBL-unit you do NOT use the TX for this. You should have the correct board orientation as well 
For whatever reason the trim or reverse H_xxxx parameters simply don’t on 3.4.3 if you change the reverse nothing actually happens. On 3.3.3 the servo will actually reverse.
You could try this:
Please go to Full Parameters and save the parameters to file. Open the file with your favorite text editor and change the parameters.
H_SV1_REV,1 …set to -1 to reverse
H_SV1_TRIM,1500
etc.
Save the file and in Full Parameters load the modified file and write the parameters to Pixhawk.
I think it is messed up because they renamed the parameters from HS… to H_SV…
Thanks for the advice. I will stick with 3.3.3 for now and get used to tuning the heli. I am new to Traditional Heli