So heres the back gorund, 2000 110 TD5
Been to a driving dayand then up on axle stands todo the rear x memeber and front PTO winch.
I had a deadline as I needed to get a tree which was now inside someones garage, well through the roof
When doing the pto I noticed back (must check that I was under the motor so was it the front?) of the engine the mud was still wet or was it oil Hard to tell as it being Scotland the climate is kinda damp.
Anway's I do my logs and I got another trip to do. I notice my expansion bottle is empty so I fill it up. 30 miles and I check - empty again. Drive back 30miles all ok, still sitting on drive after a week and ok.

I'm wondering if I damaged the rad in the mud. Whats the best way to clean a radiator?

I'm going to flush out the collant tonight as it is blue and that's what was in it when I got it. But I just got some more blue stuff for the other motorand the back reads suitable for all engines including aluminium. Could this blue have done some damage? If not what is the difference or what makes it so important to use O.A.T?

the td5 engine is designed to run on pink long life anti freez but you must have a leak from somewhere ?

Ethylene Glycol antifreeze actually slowly eats away at the aluminium parts in your engine causing a layer of white powdery oxides to form. The OAT antifreeze (normally red or pink) does not do this. Google and you shall be enlightened but there is some argument that once the layer of oxides have formed using EG then using OAT can cause leaks to appear that were sealed by the oxides.