spotty fungus

I have a community tank with some sorry looking mollies, some clown loach and some bristlenose, my original smokey pair and a few of their first offspring that my daughter wouldn't let me get rid of, these are the "dwarf" angels that are now nearly a year old and still very small.

two or three of these keep getting fungus spots, at first I thought it was Ich, but as the loach never got it, nor did anyone else, I changed my mind, thinking about it when it first happened I had a couple of guppies as well, these spots are all over their bodies, I've tried various treatments which seem to work, but a month or so later it comes back again, usually on the same fish.

Is it me and my lazy water changes, or have I got something in my tank that won't go away?? I've not had a problem in this tank before I put the angels in towards the end of last year?

Without a photo these things are near impossible to diagnose, and even with a photo, not always easy.
first things first, check your water quality, especially as you say :-

Is it me and my lazy water changes

Other than that my initial reaction was that they may be damage due to bites, or if the fish are knocking themselves on something in the tank, and the damage is becoming infected with fungus or bacteria.
A common cause of fish knocking themselves is if they are startled, perhaps by the lights turning on or off suddenly, by movement outside the tank, or the nocturnal movement of loaches, catfish, etc.
a second cause is skin flukes or other parasites which can cause the fish's skin to itch, and they scratch itches by "flicking" - rubbing themselves on rocks or plants, this too can result in damage that becomes infected.

I do check my water and it was all fine, I am wondering if its the mollies then? this is the only tank where ventrails get broken, I had some gouramis and they pecked them to death, horrid fish (the mollies), but I inherited them with a second hand tank, I certainly won't replace them, maybe they're getting upset cos their offspring don't survive lol I expect the angels have them for lunch!

If the water is good, then you're not being lazy with your water changes.
As i say, without a photo it's just a guessing game, but the mollies as culprits is very plausible.
Try separating them (with a tank partition or breeding trap if necessary) & see if the problem persists.