This sounds good so I've just had a peek at their website. Alas, I couldn't find a realistic quote for £24 - the cheapest being £22.76 for a bike valued at £100, increasing pro-rata with the bike value. A Sold Secure lock has to be used and apparently a £50 excess on claims.
On adding a more realistic bike value, the premium swiftly increases, even in our low-rated postcode.
Having ridden over a 4" fence nail earlier this week on my folding manual bike, insurance cover would have been useful but I don't think ETA is going to be the solution, at least not for me.