Many thanks Sebastian for your reply:
The PortalSettings Table does not have DebugMode and DefaultDocType SettingsName value; it only has the DefaultAdminContainer please see the following, I made a screenshot of the TabSettings table (ver 7.4.1 CE) prior to me removing them (as referred).
PortalSettings Table
Column > SettingName (some may include third party settings as well)
AddCachebusterToResourceUris
AddCompatibleHttpHeader
addresscell
addresscity
addresscountry
addressfax
addresspostal
addressregion
addressstreet
addresstelephone
AllowUserUICulture
AUM_RedirectOldProfileUrl
AUM_VanityUrlPrefix
Column_Address
Column_Authorized
Column_CreatedDate
Column_DisplayName
Column_Email
Column_FirstName
Column_LastLogin
Column_LastName
Column_Telephone
ContentLocalizationEnabled
ControlBar_BookmarkCategory
ControlPanelMode
ControlPanelSecurity
ControlPanelVisibility
coreSitemapProviderEnabled
coreSitemapProviderOverride
coreSitemapProviderValue
CreateNewPageCultureType
CrmEnableCompositeFiles
CrmMinifyCss
CrmMinifyJs
CrmUseApplicationSettings
CrmVersion
DefaultAdminContainer
DefaultAdminSkin
DefaultAuthProvider
DefaultIconLocation
DefaultPortalAlias
DefaultPortalContainer
DefaultPortalSkin
DefaultTranslatorRoles-ar-JO
DefPreviewProfiles_Created
DisablePrivateMessage
Display_Mode
Display_SuppressPager
EnableBrowserLanguage
EnableModuleEffect
EnablePopups
EnableRegisterNotification
EnableSkinWidgets
EnableUrlLanguage
Facebook_APIKey
Facebook_APISecret
Facebook_Enabled
FavIconPath
Google_APIKey
Google_APISecret
Google_Enabled
HideFoldersEnabled
HideLoginControl
IncludePortalCss
InjectModuleHyperLink
InlineEditorEnabled
Live_APIKey
Live_APISecret
Live_Enabled
LiveID_Enabled
LiveID_IncludeHelp
MaximumVersionHistory
MaxSearchWordLength
MessagingAllowAttachments
MessagingProfanityFilters
MessagingRecipientLimit
MessagingSendEmail
MessagingThrottlingInterval
MinSearchWordLength
PageHeadText
paypalsandbox
paypalsubscriptioncancelreturn
paypalsubscriptionreturn
PortalAliasMapping
Profile_DefaultVisibility
Profile_DisplayVisibility
Profile_ManageServices
Records_PerPage
Redirect_AfterLogin
Redirect_AfterLogout
Redirect_AfterRegistration
Registration_ExcludeTerms
Registration_RandomPassword
Registration_RegistrationFormType
Registration_RequireConfirmPassword
Registration_RequireUniqueDisplayName
Registration_UseAuthProviders
Registration_UseEmailAsUserName
Registration_UseProfanityFilter
Search_ReindexRequestedOn
SearchAdminInitialization
SearchIncludeCommon
SearchIncludeNumeric
Security_CaptchaChangePassword
Security_CaptchaLogin
Security_CaptchaRegister
Security_CaptchaRetrivePassword
Security_DisplayNameFormat
Security_EmailValidation
Security_RequireValidProfile
Security_RequireValidProfileAtLogin
Security_UserNameValidation
Security_UsersControl
SitemapCacheDays
SitemapExcludePriority
SitemapIncludeHidden
SitemapLevelMode
SitemapMinPriority
SMTPAuthentication
SMTPConnectionLimit
SMTPEnableSSL
SMTPMaxIdleTime
SMTPmode
SMTPPassword
SSLEnabled
SSLEnforced
SSLURL
STDURL
Store_Password
Store_Username
TimeZone
Tweetification_AppUserName
Tweetification_AutoFollow
Tweetification_AutoTweet
Tweetification_ConsumerKey
Tweetification_ConsumerSecret
Tweetification_Enabled
Tweetification_TweetThis
Twitter_APIKey
Twitter_APISecret
Twitter_Enabled
UserIndexer_ReIndex
wnsogp-sitename
wnsogp-sitetype
wnsogp-useportaltitle