Is there any secure truck parking close enough to dublin centre to allow for a night out ?
Not to my knowledge mate, but the buses are good so you will have to park up out of the city. Personally I think Dublin is like any other euro-city but each to his own.
You can park down near the docks . There was a big chip-van down there that was open fairly late, for an industrial area. They shut up shop at about 8 in the evening. There were plenty of wagons parked up on the roads near it.
There isn’t a proper lorry park though.
If you only want somewhere to park up, rather than parking in Dublin. About 30 mins drive out from the M50 there is Toughers. That is out just past Naas.
To get there, drive out to Naas. Carry straight on, onto the motorway. Take the next slip road, signed Newbridge.
At the top of the slip-road, turn left.
At the roundabout, turn right. Signed Newbridge and the Red House.
Follow that road for about a mile. Toughers is on the left.
Plenty of truck parking. Good food though not cheap. You have to ask at the bar if you want a shower. Good beer and great craic, especially with the smokers.
(As you can’t smoke inside the bar, for health and safety reasons, you have to smoke outside, next to the petrol pumps 
.)
Its been at least a year since I was last over in Ireland, so my info might be a bit out of date, you know how things can change.
Your bang on there simon,i know cos thats were i park.
There is also the NEW large 24 HOUR TruckStop that opened just a few weeks ago on the last roundabout before you get into the last stretch approaching the stenna and irish ferries ports, and VERY good it is too. a little pricey but good. soon to have SHOWERS available too. probably a first in eire. THUMBS UP