Cheers CR...
The local Isuzu garage 3 miles from where it broke was worse than useless so I left it on the transporter and asked them to take me home with it... (the very nice man didnt even try to charge me as he was heading that way).....
Will try looking for Frontera bitz... The belt is available for £15 which is cheaper than the Serpentine belt... The Frontera tensioners I have seen don't look the same tho...