Having trouble with LastUpdate

[Crumpy10]

Hi Everyone,
I am having trouble getting 'Lastupdate' to work.

I have included

DateTime LastUpdate01 "Last Update"     { channel="mysensors:multimeter:gateway:multimeter_3_3:lastupdate" }

in my items file.

I am seeing this in Openhab Log

2019-06-11 19:28:46.275 [vent.ItemStateChangedEvent] - LastUpdate01 changed from 2019-06-11T19:12:52.000+1200 to 2019-06-11T19:28:46.000+1200

Added this to my sitemap

Text item=LastUpdate01 label="Last seen" icon="network"

But no data is being displayed in my sitemap?
What have I done wrong this time??
Thanks for any advice.

[Crumpy10]

Update -:
Stop the bus, just found a solution!
For anyone else searching I changed this in the sitemap

Text item=LastUpdate01 label="Last seen [%1$tA, %1$td/%1$tm/%1$tY %1$tH:%1$tM]" icon="network"

Works perfect now!