Right; first off I can confirm that filming began on "The Sarah Jane Adventures" last Monday, April 16th (although several back-up shots not featuring the cast were recorded before then). Over the week, as confirmed by one of the site's sources, filming has taken place at Cardiff Castle and Sophia Gardens.
Below is some of the info I was kindly sent by our insider. As ever, I can't stress enough that I can't validate any claims made below - and equally, I can't reveal who my source is (or we'll risk getting him or her sacked). You'll just have to trust me. Go on, I'm told I've got a very trustworthy face...
Good evening my friend!
What a busy week we've had!!! I haven't had any time to surf the net and, as you guessed, nor have your other sources I expect for the same reason...
Yes filming started fully last Monday, and yes we were filming in Cardiff Castle. Yes we were in Sophia Gardens, and yes the nuns were ours too!!! The poster on GalifreyOne was spot on.
The read thru went great, and  is a really fab actor who won't disappoint you in any way!! A lovely lad off set too, a marked contrast to Porsha and a great relief to everyone still there from last time!! Amazingly he looks 14 despite being 19!
Alice is indeed filming the first block (ie the first 4 half hour episodes) and she is absolutely wonderful to work with. She has some really wonderful ideas, and vision on how the episodes should look... I won't be disappointed watching it at all, even tho I am there already!
Tommy Knight is the child who has had the big growth spurt - quite noticeable to everyone, but luckily not enough to distract, as  is of similar height.
None of the first 4 episodes have titles that I know of...maybe they are keeping it secret from us as well????
Yasmin IS adorable; highly talented in my view and very professional at work. The fact that none of the children are remotely big headed, or touched in any way by the magnitude of the parts they have, is a big plus for production and adds to the charm that they possess individually.
We're not allowed to take piccies on set I am afraid...tho maybe next time I am somewhere more public I could try and pretend I am a passerby, and take a sneaky snap or two! Annoyed with myself now...Sophia Gardens would have been a perfect opportunity (as would Cardiff Castle really, as they were still allowing visitors in, and we were waiting between shots in full view of them all...!)
12 more weeks to go, and I can't believe how fast this one went...roll on tomorrow!
 refers to the actor replacing Porsha Lawrence Mavour. Naturally it'd be unfair of us to reveal his name before any BBC Press Release - so for now, his name remains a mystery. Rest assured though; the time will come when you'll all get to learn his name!
With filming underway, expect an avalanche of set reports and - possibly - tabloid attention over the coming months. Filming lasts 12 weeks, and an early September broadcast looks likely (although schedules have yet to be finalised, and won't be until mid-August).
I'll update you some more when news comes in.