just changed the exhaust flex with a milltek one. for some reason its beeping every once and a while. do I need to buy a hand held like blue fin or is it just the sensor? only have a better rear muffler that's it.

Fitting a flexi wouldn't normally do that

I remember the flexi fitting instructions saying not to clean the sensor so sounds like it is damaged easily, or maybe there is a leak causing faulty readings.

When I fitted the cutback system on mine it upset the heater element wiring in the Lambda sensor. That was just by moving it 2 inches!
Unfortunately the only way you can find out is plugging it into a scanner

i took It to ford, they plugged there computer to it but found no codes. - when I use vcads on Volvo's and they have a running problem u leave them running when testing. ford recon it doesn't matter!

Fault codes are stored.

What's beeping?

its a quick red beep don't have time to see what's showing. but it can beep down the hi-way or in the city

When you say a 'quick red beep' what do you mean (a sound can't have a colour lol).

Do you mean you get a red light on the dashboard, a beep, and an error in the MFD? Is it a facelift with the MFD or a pre-facelift without?

Given the limited information available I'd be suggesting a faulty ABS / wheel speed sensor or throttle body issue. Both of those will cause a "Engine System Fault" with the red bleep. Exhaust issues will only illuminate the engine management light (which is orange and will stay on for a bit).

Otherwise you're going to have to be a bit more specific with regards to the error or the beep, as it could quite literally be anything.

brought the car into work today, found and exhaust leak from the 2nd sensor after the cat. could this be the issue?

More than likely, i will make that sensor give really odd readings and will confuse the ECU. Did you tighten it or is it a case of a new one is needed?
The front sensor was loose on my car when I bought the car and kept coming loose every so often. I ended up replace the exhaust flexi and I found the thread was buggered. Managed to clean it up and the car has been running a bit better low down in the revs since