I've got one of these (it's great)...

...however I've steadily managed to lose the straps one-by-one generally through idiocy and schoolboy errors.
Can anyone recommend where to get replacement straps? Everything I seem to find on the web is about £4-5 per strap which just seems pricey. Anyone got any suggestions? The red ones on sale in Halfrauds are very long, tried those, not ideal...
Thanks in advance.

