Tried to play a film tonight in my cld-1450 but it's not recognising the discs. Opened it up and you can see the laser mech moving back and forth but it won't register the disc. Any ideas?

Ok so it just fixed itself. After 30mins of trying to get it working I post on here then try it one more time and it spins up.

Is playing fine now but would be concerned as to why this would of happened.

From your description it seems like it is trying to focus and lock onto the signal but fails.
I believe it won't recognise whether it is a compact disc or a laserdisc either?
Maybe a new loading belt would help?
I have had a similar issue in the past with the cld-1750, but haven't experienced it since.
The disc I was trying to play, felt much thinner than a regular laserdisc. After multiple attempts, it would play in the end.
However, the player had been sitting for a while and wasn't used very much.