The Dolan is a good bike and far better than the ones you listed. But for that sort of money you’d be better off going 2nd-hand or picking up a frame and kitting it out yourself. The frame is by far the most important part, so get one made from decent steel or alu. Wheels next, avoid the heavy deep-section rim nonsense and look for something light. Then a good crankset, 165mm and around 46t chainring, and then pick up a bar and stem, and the rest - brake & lever, saddle, seat post and pedals. You could easily do that for under £500 if you scour the ads here.
The Dolan is a good bike and far better than the ones you listed. But for that sort of money you’d be better off going 2nd-hand or picking up a frame and kitting it out yourself. The frame is by far the most important part, so get one made from decent steel or alu. Wheels next, avoid the heavy deep-section rim nonsense and look for something light. Then a good crankset, 165mm and around 46t chainring, and then pick up a bar and stem, and the rest - brake & lever, saddle, seat post and pedals. You could easily do that for under £500 if you scour the ads here.