Thanks for all the replies everyone.
A little sniffing around uncovered this ...
Latest firmware is T-TDT5DEUC-1023.0, date 22.12.2010.
Changelog Details:
1. Title
2010 Model Firmware
2. Applicable Model
LE**C3, C4, C5 Series
3. Carrier or Corporate Customer
Open Market
4. Description
T-TDT5DEUC-1023.0
. Watching ''picture'' on media play error with new s/w of I-phone/I-pad.
. Update the energy requirement for Australia
. Improve PDP 4 Series 50'' (U2P Module) Reddish picture(Red dot) issue