Hi hargi 01,
If your company is no longer carrying out any trade in the UK and all trading/activities of the company are taking place in Portugal then it is possble that your company may be deemed to have migrated to Portugal.
If this is the case guidance can be found in HMRC's CTM34100 - Residence: outward company or permanent establishment migration: contents
Your question in relation to your company paying you dividends and the implications for your tax position as an individual in Portugal could be perceived as a tax planning type question and HMRC cannot offer any advice on tax planning. For this question you may wish to seek professional advice.