I think the fact of the matter paddy112 is that, ignoring the legal implications, that no one will be selling an ebike that's capable of 25mph for 20 miles with no pedalling for £600.
Even 2nd hand, you'd be looking at a good £1500 at least.
That kit you linked - it's big, it's heavy, it's a pig to pedal unpowered and even with the 20ah battery it still might not make it 20 miles. People on here are knowledgable and know that that kit would be a pile of c**p and if they were building a bike that could go that far @ that speed, they'd be using a good quality bike with good brakes and suspension, so that would bump the cost up right away.
*This* is the kind of bike you're asking for and look at how much that sold for 2nd hand.
Even 2nd hand, you'd be looking at a good £1500 at least.
That kit you linked - it's big, it's heavy, it's a pig to pedal unpowered and even with the 20ah battery it still might not make it 20 miles. People on here are knowledgable and know that that kit would be a pile of c**p and if they were building a bike that could go that far @ that speed, they'd be using a good quality bike with good brakes and suspension, so that would bump the cost up right away.
*This* is the kind of bike you're asking for and look at how much that sold for 2nd hand.