On SKYPE, try typing this on your message box "html" when you log on and you'll be able to see the dates and time fo your conversation.
Highlight the whole conversation from whatever days you want...it can show you the ones from yesterday; the last seven days and the last 30 days.
Then right click - copy - and paste it on a blank document and save it.
If you only have 21 days of stay in the Philippines you do not have enough time to bring your wife and children back in the UK.
First of all, when you apply for the marriage licence you will have to attend a seminar which takes only a day but the Civil Registry will require you to have the Attendance Certificate before they start to count the 10 working days before you get Marriage Licence and get married.
Secondly, the endorsement of the Marriage contract to the National statistics office can sometimes takes more than a month.
And lastly is the spouse visa application and the visa for the children. It will take time to gather all the required documents and the time waiting for the release of visas.
If you will read further about spouse visa, you will find out how fast or long it will take.
Hope that gave you bit of help.