From your description is doesn't actually sound like the groundwork's were ever on the critical path and therefore this question is moot.
However, if they were on the critical path I would generally say you keep the time as they will be based on an impact on the Accepted Programme immediately before the event updated to the date when the event arose. That you had plenty of risk in an activity bar is your choice and that doesn't get converted to float the project or employer can use until after you have completed the activity.
There are obviously lots of facts here that would need to be unravelled to get a proper answer.
However, if they were on the critical path I would generally say you keep the time as they will be based on an impact on the Accepted Programme immediately before the event updated to the date when the event arose. That you had plenty of risk in an activity bar is your choice and that doesn't get converted to float the project or employer can use until after you have completed the activity.
There are obviously lots of facts here that would need to be unravelled to get a proper answer.