You can request a MATZ penetration, but remember you do not need permission to enter a MATZ. It is very wise of course, but I would normally
a) Not be so low as I need to 'penetrate' the MATZ unless overlying airspace restricts me ie. fly above it
b) Be receiving a RIS from the unit who controls the MATZ anyway (if possible). If there a are a number of mil airfields en-route then they will normally had you off between each other (ie hand on your details to the next station)
If entering a MATZ on the weekend (ie no response from the unit), when and if you cross the final approach path, use caution in case you meet someone on final for some obscure reason. If the ATZ is also inactive, you can fly through it as well.
I dunno about London Info having Radar data, but I suspect Scottish Info do, otherwise why would they assign me a sqwark and provide RIS?
Cheers
EA