So we're nearly there in North Africa, this should be fun.
Quite a lot could change from OTL given the changes so far.
Firstly the British have a much stronger armoured force than OTL with a slightly improved doctrine. This is, apart from a couple of times, not actually that important. It will be hard for the British to win some of the battles they fought more thoroughly than they did. There were some times British forces in Mk VI lights ran into more capable Italian tanks so having either of the Valiant's or even an A9 in that scenario instead turns the table's and prevents some of the few Italian successes. There will be other advantages though, the Valiant's will be harder to knock out or damage over the OTL tank. That reduces stresses on the maintenance crews as well as the supply of spares needed etc.
Secondly the Valiant should be more reliable than the OTL tanks. The tracks at least won't wear as fast so will need replacing less frequently. The cumulative effect of that and other reliability improvements will be quite large. Firstly the lower number of Breakdowns means that the British will have more tanks available at any given time. Secondly the fact fewer spare parts etc will be needed means that the logistics will be eased quite a bit. This is even more true as the Valiant sisters will share quite a few parts for things like running gear etc. All that improved logistics will be able to carry more fuel and ammo etc allowing the force to move further and/or faster.
Thirdly, the Valiant Infantry despite using a different fuel will be far more fuel efficient. That allows again for slightly improved logistics as you can carry less fuel per mile traveled. Now there is a trade off in that the Valiant Cruiser may use more fuel per mile than tanks like the A9, A10, A12 and Mk VI. There is room to take up the slack if needed. The thing is that may not be entirely true. The more powerful engine in the Valiant Cruiser may mean it can actually be as or more fuel efficient than the OTL tanks. That is a part of my next point.
Fourth, speed. The Armoured force will be abe t travel faster if needed. With no Matilda II slowly crawling across the desert the British will be able to move the whole force faster when required. In situations when the force is slowed down by other issues the Valiant's will be taxing themselves far less than the OTL tanks they are replacing. That means that one they will need less fuel making them more efficient and possibly making the Valiant Cruiser as fuel efficient as the lighter tanks. Two they will be taxing both their engines and running gear far less meaning improved reliability. They again add up to a better logistics situation. Another potential benefit of speed is it may mean the Italian's are far less organised due to the faster British advance leading to a faster collapse and some of the battles fought OTL not happening. Again all to the good for Britain.
So what does this all mean.
Well, there are a few potential scenarios these changes could lead too.
1, The whole thing could go pretty much as OTL, very unlikely however. The most likely way this happens is O'connor halts but for a long time and Wavell pulls his troops for Greece.
2, Britain advances to much the same place as OTL but gets there sooner. Because of a better supply situation and less worn out tanks O'connor continues before Wavell strips his force for Greece.
3, Britain advances and keeps going past where they stopped OTL. How far they get though depends.
How far can Britain get.
Sirte, thats how far, at least before a major rest and resupply. Will they get that far, depends, but by the time the British have got that far, or close even, they will need to stop.
What happens next.
The Germans that's what and what they do depends on who is commanding them. Either way the tanks the German will bring won't stand up to the Valiant's much better than the Italian tanks.
Outcomes.
1, Done by mid 41. The British either blunt the German attack or if the Germans don't attack then the British do. It could be British in Tripoli by May - July. Possible outcome this one.
2, Done by late 41. See above but more back and forth. Again as possible as the one above.
3, All over some time in early to mid 42. To be honest this is the least likely of the outcomes.
Wildcard the French get involved. Thing is why do they get involved, is it because they were pressured to by the Germans or because the Germans got desperate and annoy the French into getting involved. Then you have the question of how are the French involved, is it just letting the Axis use Tunisia or are they actively fighting. Who are they actually fighting (hint Germans).
Other wildcard, Barbarossa. If the British manage to look like they are about to win just as or after Barbarossa has started the Germans might decide they don't want the distraction of North Africa.