Thanks
@Webbo2, very useful feedback. I recognise P Blakney from BR, I wonder if he's migrated to here, too (I'm a recent BR refugee).
I am aware of permanent distortion of TPU tube when inflated on its own without being in situ (low yield point?). Just wanted to know if electrical tape repair hack is worth a try at a pinch but I'll get a purpose repair kit just in case.
I still have quite a few butyl tubes and loads of Rema patches and vulcanising glue so I'm not a full TPU convert yet.
So, given the TOU yield point, is it wise to get a TPU tube that's one size bigger than intended? For example, for a 28c tire get a TPU tube that's sized for 30-35c instead of a TPU sized for 23-28c (or even up to 30c)? Just curious.