Greetings, GinDottydotto (imperative everyone on this thread has a dotty name) reporting in after beach day.
So we did go to Colwyn Bay (I still want to go to Formby as it looks lurvly but have to get around DH who is allergic to flat landscapes 
)
I had also forgotten about the Anthony Gormley statues which I would love to see, so have pencilled that in for another day. 
We live West Mcr near M60, so as close to N.Wales as you can get while still living in Mcr 
so the drive wasn't too bad (1.5 hours) and ds is a good traveller (aided by his deep and abiding interest in anything with wheels - convenient on a motorway), though it was about his limit.
The beach was great 'cos it goes into the sea very very gradually so you can paddle a fair way out and still be knee deep. This was a big plus as all ds wanted to do was paddle so it was all we needed!
Didn't even get the bucket and spade out which was good as it was a shade cool (gentle cool breeze) for sitting around, and, as the sea comes right up to the prom wall all the beach is firm and damp, there is no dry fluffy sand area for comfortable sitting.
I would say it is a running-around beach not a sitting beach unless you have a picnic rug with a waterproof back. So will bear that in mind for future trips.
Dog enjoyed a good gallop round (frisbee was a good choice) and it has worn his toe nails down a bit!! We left the beach as clean as we found it.
No arcades/tacky shops that we found, but were picnic tables, ice cream kiosks etc.
We had morning at beach then went inland a bit (snooze in car for ds) for woodland walk and ace dog friendly pub nice pub for dinner. Then drove home with tired and stuffed-full ds asleep. Home by 8pm.
Great day, but would say Colwyn Bay is limited from the point of view of seaside entertainments (not a prob for us) and isn't necessarily good for sunbathing (from the point of view of damp sand), but AOK for an active paddle/sandcastles/shell collecting type day