From my experience as a specialist family solicitor, I note that there is no nationally set "standard" for child contact arrangements. The Children Act 1989 looks at what is best for the children, and this can vary from family to family, because every situation is unique to some extent. Studies tend to show what's most important is that children retain contact (whether direct and/or indirect) and an indentity wth both parents, although in some (usually more extreme cases) little or no contact with a parent might be necessary to safeguard the children from harm. 50/50 isn't necessarily what's best for the kids.
Therefore, I always recommend starting with considering what you feel is best for your kids - you know them and your personal circumstances best. Also bear in mind that whatever decision you make, that it should be based on your kid's best interests.
Also, thinking about "what a court would say" is the wrong way to go about thinking about your situation. By far the majority of cases are agreed (sooner or later) by the parents; the whole system is geared towards a judge making a decision only as a very last resort. it all comes down to the fact that whatever issues you have with your ex, you are still the kid's parents and all proper family law professionals will want you as the parents to find a solution, although sometimes professional help is needed by you both to achieve this (such as via mediation or collaborative family law process).
I appreciate that this is not a black and white answer, although in family law there seldom is one definitive answer.
So, good luck. Hope this helps in some small way.
If you get really stuck, I recommend you seek help via a member of esolution, the family lawyers association - www.resolution.org.uk/ or contact via my MN profile.