That's strange - I have the official Douglas clan motto as "Jamais arrière" which means "Never behind". When I say clan motto, I am referring to the motto used by the Clan Chieftain as the senior Douglas.

Nowhere in any of the 18 different mottoes that I can find for the name of Douglas, can I find "What Tyde". In fact, I can't find 'What Tyde' in any of my list of mottoes. Here are the mottoes use by different families of Douglas surname.

Here are the 18 mottoes I found that are used by the surname of Douglas:
Audax et promptus
Do or die
Fortis et fidelis
Fortune le veut
God for us
In cruce glorior
Jamais arrière
Lock sicker
Meliora sperando
Per varios casus
Petiti ardua virtus
Pro patria
Quœ serata secura
Sapientia et veritas
Spero meliora
Sursum
Tandem fit surculus arbor
Meliora speranda

Sorry I can't help any more.