I have just exchanged my Calor Lite cylinder and got another lite on return? As you know these bottles were supposed to be discontinued and exchanged for the heavier bottle.
I asked the Calor agent what had changed, he said that calor has not made enough of the old style bottles to replace the lite version. Since Easter 2018 Calor has been reintroducing the calor lite bottles that have passed their quality checks.

My bottles usually last two years so hopefully they will have the new caravan friendly bottle in service when I come to exchange it again..

I was at Attwoolls camping yesterday and was told that Calor had contacted them this week to inform them that they do not intend to replace the lite bottles with anything, and when the lite's go out that's it, back to heavy.
I don't know if this is true, there's nothing on the Calor site but they were never ones for keeping their customers informed.
Dave