Methods with the same name as their class will not be constructors in a future version of PHP; SlideDeck2Widget has a deprecated constructor in G:\wamp64\www\test.darrenjehan.me.uk\wp-content\plugins\slidedeck3-personal\lib\widget.php on line 35
Thanks for letting us know this issue.
The issue belongs to the slidedeck3-personal plugin. I have contacted the Sldedeck team regarding this issue.
Are you facing any issue with its functionality? Are any settings not working?