So to add to my post above, hopefully someone finds it useful. For me the real key for my purchase was being able to trial a similar bike from a retailer nearby to my home or office before purchase. So that it was a known entity, ticked the boxes I needed and if/when I got problems I didn't have a complex job of returning the bike.
I found London a surprisingly barren area for Kudos bikes. It does seem like the electric bike market is quite niche and has a number of small players who have smallish stocks of specific bikes which made it hard for me to compare, having to travel longish distances over a number of weekends to see different bike suppliers.
Also during trials, I found some bikes had way too much lag between applying pedal power and the motor kicking in. The good news for Kudos, although I didnt get to trial the Stealth, is that I trialled one of their e-MB, I think the Typhoon. And frankly, while it was not the type of bike I wanted, I was actually quite close to buying it, as it was actually a pretty good bike and I realised I had to compromise somewhere.
In the end it came a close second to the BH eMotion EasyGo Cross from Fully Charged. The shop, while a bit of a distance from me is at least in London and actually had the largest range I had seen in any electric bike shop, making trialing much simpler. They were also very happy for me to take bikes out to trial there and then, unlike when I went to Halfords, where the service was atrocious and the staff completely uninterested. So while I hadn't ridden this specific "Cross" bike, I had ridden the "Race" single speed and loved that too, but realised I needed gears for the hills I would be climbing!
In terms of reviews for my e-Bike. I have now done about 800kms on it in the last few months and have certainly found it a great bike, but also some things I would want to change now. For sure, I would look at getting a bike that has disk brakes. The v-brakes have already had to be changed and the second pair are already getting quite worn! I travel through a fairly hilly area (not the alps like, but enough for me - North Harrow through to Sudbury) and find the braking puts a lot of stress on the bike. Although if you are able to change them yourself its only a cost of £6 per set.
I would also like better gearing ratios on my bike. The current 21 set of gears at such low ratio (in my view) is wasted. I don't really ever use the 2 lower sets on the central crank. The motor is so powerful even on steep hills that it can get you to 8-10mph without much effort on my part even in top gear. And very easily in the lowest gear on the largest central ring!
And finally the perennial problem of the battery! While I love the fact that the battery is tiny and unobtrustive and actually really easy to remove and charge. I expected it to be able to last longer than it does. So while it doesn't cause me any massive issue, I do have to cart my battery around with me everywhere. I do 12 miles each way and if I use full assist (not as fit as I used to be and by the end of the week I need it), the battery can be drained down to 30% remaining on one trip, even when I spend a fair amount of time over 15 mph when the battery cuts out... although I will say this about the battery, it seems to be much smoother on cut out that some of the other bikes I trialled which were often jerky and not a comfortable transition. And it happens a lot in London with the stop-start traffic!
Just to add for those interested in terms of hill pull ability, which is something I worried about before purchase. I find Harrow on the Hill the hardest part of my journey. And it is true that on the steepest part of the hill, especially going south, the motor does start to struggle and requires more effort from myself. It seems according to doogal.co.uk the maximum gradient ascending:10% at 0.4 km (about halfway up the hill) using this data:
Location Latitude Longitude
Location 1 51.56937 -0.346874
Location 2 51.567841 -0.33955
Hope this helps! And apologies for my lack of brevity...