I'm no longer getting the unread since last visit or unread replies option?   

Are you sure you don't have the stats header minimised at the top of the page. Is there a plus or minus sign at the top right of the page?

Er no....

Still losing posts... had some 15 posts on one page last night when i logged off ( the 180+ pages of unread have gone for good)... log on this morning and only 8 posts.
For some reason i dont get the options that Nino does to "click unread"

In fact "unread"is highlighted in toolbar. Clicking this OR "unread since last visit" has same results.

This forum worked well for me until the options to change page colour appeared... ive completely lost the history of unread posts

The option to change colour has nothing to do with this issue. It started happening when I upgraded from 1.1.11 to 1.1.12. Can you please attach a screen shot of what you mean when you say you don't get the same options as Nino?