[TYPO3] TV FCE issue

[Simon Browning]

I've got a site that has been working fine for ages, but for some reason 
today all of the FCE's have dropped the < & > symbols, so the output on 
the site is like below.

h1link 8marketing driven designbr //link/h1

I can see in the tx_templavoila_flex field of tt_content that it has the 
symbols stored as the &lt;h1&gt;&lt;link, which I believe is correct, 
but I'm not sure why they're not being replaced on the site.

Even in the rte in the backend they're showing up improperly - in fact, 
if I correct them in the rte & save, it swaps them back to the incorrect 
version.

Again, this just happened today all of a sudden, the site has been fine 
for six months.  In case something went wonky with the TS Config on the 
root page I copied replaced it with one from another site that is 
working fine, yet no change.

Any hints or boots in the right direction would be most appreciated.

Thank you.

Simon