It's only a very small handful AFAIK.
Which, surely, is more a case of "evidence that going beyond 28 days to 42 is not needed"?
No one has made a convincing case for the 42 day limit. [IMO

]
The Govt only won the vote (narrowly!) due to (alleged

) backroom deals with a certain party, plus the usual "We know you don't like this bit of the Bill, but you have to stomach that & vote for it anyway as loyal Labour MPs, OR ELSE YOU'LL DESTROY GORDON'S GOVERNMENT!!!!! OMG!!!!"
Why isn't 28 days sufficient to stop them blowing up "a bus load of kids"?
As for "the right to live without violence must imo out way a suspected terrorists right to carry out there mission.", erm... that's not the argument.
No one is saying that suspected terrorists have a "right to carry out their mission".
But
suspects have the right to not be detained for excessive periods without charge or trial, the right to be promptly informed of the reasons for said arrest & the right to be
promptly informed of the charge...
We already had the highest pre-charge detention period in the West with the old 28 day limit (higher than the US, higher than Europe, higher than Turkey even)... why the need for 42?
And as David Davis said in his resignation statement, he said he feared 42 days was just the beginning and next "we'll next see 56 days, 70 days, 90 days"...
Remember, Blair wanted 90 days the last time this came up... 28 days was actually a compromise, after the 90 day provision was defeated in Parliament.
Terrorism Act 2000: 48 hours, could be extended to 7 days with permission from a judge.
Criminal Justice Act 2003: 14 days.
Terrorism Act 2006: 28 days.
Counter-Terrorism Act 2008: 42 days.