How do I delete a batch of pictures ? I can only find a means of deleting photos one by one , whereas on all my other cameras I have been able to delete all images on the SD card.

SOURCE: How to delete all images from camera card of Sony DSC-T5

Don't feel like digging around for the Manual, but have you tried:
Menu- (press down twice) to Memory Stick Tool- (press right) to Format- (Press centre button) to OK - then confirm Formatting the memory stick?

I imagine this would reformat the whole stick, deleting everything on it in 1 go. Alternatively... you could just delete them all via connecting the camera to your PC...

SOURCE: How can I delete "locked" images?

Go to the menu on the camera and navigate to the FORMAT command. Formatting the card in the camera should clear all photos.

SOURCE: Is it possible to recover my pictures?

I have had success with this... Download the program
http://www.asoftech.com/apr/

You have to use a card reader either on your computer or an external USB card reader. Put the card in the card reader, open the recovery program, then select the drive where files are deleted, then press "Start" and wait for it to do it's magic.

SOURCE: Can photos that were accidentally deleted from a SD card be recovered

yes, you can recover deleted photos from sd card with sd card recovery software like asoftech photo recovery, here's the steps that helped me

1. Do not save any new file to memory card.
2. Connect your card to computer. You should see memory card shown as a drive letter (like H:) in My Computer.
3. Download recovery software, recommended one is this photo recovery (simply because i was using it and it worked)
http://www.asoftech.com/apr/
4. Install and open the photo recovery program, select your memory drive, and click 'Start' button to start scanning process which will find your deleted photos.

SOURCE: accidentally deleted precious photos off memory card

dont worry, you can recover deleted photos from camera with camera recovery software, a good one is asoftech photo recovery which you can download from link below
Photo Recovery Software

Here's a good guide you can follow
Camera photo recovery

good luck.