My mother wants to get a life insurance policy through Colonial Penn, but we are planning to move permanently to England in about 2 and a half years. Will this policy still be valid there or???

As long as she is truthful on the application and they accept her. Just in case Colonial Penn gives her issues about being an ex pat, there are companies that only ask about her travel past, not her future. Most independent insurance brokers should be able to track a few of these down for your mom to consider.