I bought the Pinnacle Iroko 3 yesterday and it's a superb bike but the frame size is just too small for me, I'm 6'4 and weigh 108kg the frame size is 19.88" / 50.5cm

I cant get a refund only an exchange and the only bikes within the same price range and are 23" / 58.42cm in stock, are the Trek Roscoe 9 and Scott Scale 960 - I'm restricted to Evans Cycles only.

Could someone explain to me what bike is the better bike and why, what are the key differences etc