I've made some progress, after the first size modification, I had to change in 'move-feedback-new-wrapper' the 'overflow-y' attribute from 'scroll' to 'initial'. My page now looks like this:
I'm now trying to figure out how to make this permanent for all reviews within Chrome/Chromium.
Will update once I do.
I have the solution - I'm using Chromium so these instructions are for that browser and its derivatives.
1). Install the 'TamperMonkey' browser extension.
2). Enable developer mode: Go to; chrome://extensions (there's a button in the top right corner)
3). Click on the TamperMonkey extension icon and select 'Create a new script...'
4). Copy the code included / linked below and replace what's shown in the TamperMonkey editor with it.
5). *** IMPORTANT *** go to a game, click 'Start Review' and then once you go get to Move 1 (move=1) REFRESH THE PAGE! - If nothing happens, click on the TamperMonkey icon again and make sure the script is Enabled.
6). This should create the space required to see both the 'Move Played' and 'Best Move' Bubbles at the same time going forward, without the need for incessant scrolling.
(to begin with the extra space is a little redundant as there often isn't a best move to show in the opening but you'll just have to live with that - also if you've played the Best Move during the game)
The Code; go to the below link and copy the code into the TamperMonkey editor. Make sure that // ==UserScript== is on line 1 as per the image included.
Happy Reviewing! 
Hello,
The new game review no longer shows both the 'Move Played' and the 'Best Move' bubble at the same time. This is very frustrating. You have to scroll up and down to see them for every move, never seeing both simultaneously.
I'm trying to figure out a way to get round this by altering the underlying code in Developer Tools.
As you can see below, I've managed to expand the window area ' .move-feedback-new-component ' from 452x163 to 452x326 which creates enough space for the two bubble boxes and everything below adjusts accordingly.
However, I can't figure out how to make the top bubble 'Move Played' appear at the top of the area. I still have to scroll up and down where they now sit.
What do I need to adjust in the code in order to properly place the two bubbles to start at the top of the expanded area in order to make this work?
I hope that's clear. Any help would be greatly appreciated.
Thanks and regards,
3dmo