Sorry, do not know any good instructors in Mullingar. Any instructor's name you do get, check here ADI Registered Instructors
Unfortunately being on that list is no guarantee that they are any good.
Regarding coasting, any good instructor should be able to sort out that wee problem immediately.
For example, you negotiate most junctions/corners in 2nd gear, so approaching a junction brake way way down, depress clutch, (if necessary continue braking slightly) change to 2nd, release clutch. Have this done, say a half-car length from the junction. Then NO gas, brake or clutch, (Feet OFF everything) let the car take you through the junction. Practice quiet junctions first, where you will not be distracted by other traffic..
One reason I find why people coast, they do not brake down enough before changing gears. Its all about control.