Nice report again Paddy and it's great you can make use of these perpetually clear Sunday nights! I swear it's the night with the highest frequency of clear skies. Conversly Sat night is the worst
Orestis, to check collimation of the laser, put it in a V-block, turn it on and aim at a wall. Turn the laser, if the dot's motion is circular/arcing as you turn the unit, then it's not collimated but if it stays in one spot it's okay.
However, the laser is really only useful for tilting the secondary so that the beam hits the centre of the primary. For initial centering of the secondary under the focuser, a cheshire is recommended, as is for completing primary alignment after you centered and aligned the secondary.