Rover owners: Red stains on the cylinder head, IMG failure?

Hi everybody! I'm a little worried because I've been noticing strange red stains on my Rover 200 K-series 1.4cc.
Specifically they're on the cylinder head next to the inlet manifold, near the first (and fourth) cylinder. Apparently, they seems to be dry rusty powder residues. At the same time I've been noticing a very tiny water leak looking at the expansion tank water level.

Here are six high resolution pictures of the stains:
1. http://ift.tt/2d3BX2s (Stains locations)

2. http://ift.tt/2dGYGiK (Stains behind the Cylinder Head, next to the first cylinder and the Inlet Manifold)

3. http://ift.tt/2d3CK3w (Same stains of the previous picture)

4. http://ift.tt/2dGXM60 (Another stain near the first cylinder. A similar stain-deposit is also to the other side of the Cylinder head, next to the fourth cylinder.)

5. http://ift.tt/2d3C1iY (Stains on the right side of the engine, next to the fourth cylinder)

6. http://ift.tt/2dGYwrT (a closer look at the stains of the previous picture)

According to you, could those stains reveal an inlet manifold gasket failure? I replaced it 30.000 miles ago when I replaced my old head gasket with the newest XPart "Multi Layer Steel" (...consequently, the fitted IMG "should" be the green one).
Someone suggested me to try a pressure test of the coolant system to find the leak, but I'd like to avoid it because I'm afraid the high pressure of the test could damage the engine!

Advices are really welcome and very much appreciated! Thank you!