Several issues

1. Web page (wxlocal) uploads do not always happen. The local file gets updates, but not always uploaded according to the schedule I set. It was set to update, and upload every 30 mins. I had to set the upload to every 5 mins to make sure that the upload does happen, even if one does fail.

check the ftp logs for clues (could be problems with your ftp server (slow, timing out, etc)

2. Some custom tags are not working. One I can remember doesn't work is the Metar last report time one.
not enough information provided to help you
3. Several webcam issues. If I close the WD webcam program that runs in the tray, I can not start it again by clicking on "Control Panel >> Web Cam >> Setup/View direct live web cam capture"

correct
just start it manualy, via double clicking on the program itself
this is designed this way so that people do not start multiple running instances of the program

4. Web cam overlay settings are very screwy. Position is an issue - "left" & "width" seem to effect eachother. Trying to get my overlay to the bottom right corner was difficult. "Size +/-" is mad! Font size settings get lost when the program is restarted.

you dont say which version

yes this function is a bit fininicky, but thats not my code thats the problem ,its the componenent I have used

5. Staying with the web cam, when it's running my mouse pointer becomes jerky due to fairly high CPU usage. I have tried ticking all the options for lower CPU usage, but they make no difference. Appart from the web cam occasionally stopping, it normally works fine, and gets uploaded fine to my site every minute.

untick keep alive, using the latest version (only works if not using the save every 1 second)

the high cpu use depends on the web cam driver (some are worse than others (I do not have any problems here myself))