I too could not find a relevant contact for Tesco so tried phoning their Tech. Support (surprisingly Hudl is still listed on the products supported page).I was put through to the Hudl team but the chap there was not very helpful - he seemed to think that the old server had bee dis-continued.IAfter looking through some old forum posts I tried flashing my Hudl with a custom Rom ( TabbieDroid v1.5 download (includes update fixes) - http://www.mediafire.com/?bnjtbcda415kuqo )
The tablet started up and displayed a message "Android optimising apps 0-39 ,but when this completed it continued with the start up screen until it stalled at the wi-fi page ,as before. It does seem that this internet connection is essential and it is poor practice by Tesco if they are have now shut it down.I know the Hudl is an old model but it was very successful in it's day and there must be quite a few still in use.I only used mine as an e-book reader but it was a useful item and a handy reserve for web browsing etc. Let us hope that Tesco re-instate the server after your contacts.