Power steering fluid leak

Hi all
My 200tdi has the old tin can style power steering reservoir and I think it's been overfilled. I know the system is supposed to self bleed from the wee hole in the lid and there has been a constant "leak" from here for a while. I have also got a leak from the pump.
A couple of questions if I may:
1. If it's overfilled could this cause a leak from the seal in the pump due to over pressure?
2. I think there should be a dipstick in the reservoir but I don't have one for some reason. Can anyone tell me what depth the fluid should be in the reservoir if it was at max on the dipstick ?
Thanks in advance for your responses

if its over filled it will just leak till its not over full wont affect the pump
halfway up
id guess pump seal is sucking air in causing your leak

jamesmartin said:

if its over filled it will just leak till its not over full wont affect the pump
halfway up
id guess pump seal is sucking air in causing your leak

Click to expand...

Thanks James it's more like 80% full. I think I'll draw some of the fluid out. I'm constantly soaking up excess fluid around the lid.