Ofcom, the regulator for the communications services in the UK, states,
Broadcasters must ensure that television advertising and teleshopping is readily recognisable and distinguishable from editorial content and kept distinct from other parts of the programme service. This shall be done by optical (including spatial) means; acoustic signals may also be used as well.
Unfortunately, every main owner of channels does the breaks differently.
In Comskip, detection level 111 seems to work for UK tv as a generic setting. Did you try to use Showanalyzer for commercial detection?
MythTV has an entire section dedicated to UKTV and Comskip.(Commercial detection in the UK - MythTV Official Wiki)
Comskip themselves may be able to give you help. Comskip Support Forum - Index page