From BOF Planning Guidelines, the Mini Relay should be TD2, which is:
Routes and route choice:
Route all along obvious line features such as tracks, paths, fences, walls, rivers, large ditches and very distinct vegetation boundaries.
No route choice, including at the start banner.
Number of controls:
Controls fairly close together (350m maximum).
Leg lengths should not vary greatly.
A control is not needed at every Decision Point, but there should be at most two Decision Points per leg.
Control sites:
On the line feature along which the competitor is travelling.Obvious other features close to, with the banner clearly visible from, the line feature, e.g. knolls, boulders.
Also from BOF guidelines:
It is preferable that all courses, including the Mini Relay, are gaffled to some extent to avoid following. However gaffling should be fair, and in particular should not try and 'trick' juniors into mis-punching.
The mini relay is the first race to start at 10:00am
I have some issues with these guidelines in general, and some observations about this years BOC mini relay.
Only few clubs have 3 M/W12- who are all TD2 competent/competitive and at the BRC. As a result, there's a big difference between the fastest & slowest in the field, with some juniors running to "make up the numbers" so that other juniors in their club get to have a run. If it's a true TD2 course, this could be tricky for them.
I can understand showcasing the start of the mini-relay by starting them off first, but this sends the juniors out into empty forest with no other orienteers around from a safety point of view. Would they be better off starting later when there are more people around (not that I'm advocating in any way that junior should rely on other orienteers to get them around their course).
Mini relays have been variable in terms of their technicality, and this weekend the courses were the most technical I have seen.
The first 5 teams who had their 3 runners over the finish line were disqualified. Not to detract from the winning team, this says to me that there was an issue with the courses. These dsq'd teams were not full of inexperienced orienteers (they should all have known better, but we all know what the pressure of relay situations does).

The 3 courses run by one of Chasers relay teams.
There were 9 different courses that made up the mini relay gaffles, with the runners not equally distributed across the courses. The first gaffled control was the first control, having already had to run straight past the spectator control. The majority of the first leg runners had the closer first control on the knoll, while the minority had to run past it, & everyone punching it, & on to the next control. A difficult thing to do as a senior, never mind as a 10 year old. By the time you have seen what the code is on the control everyone is punching, worked out it's not yours and which way to go to get yours, those who have punched it are well ahead.
Number 5 is not a TD2 control (in a ditch, 30m or so off the path, out of sight and not even an attack point), some of the legs are over 350m long on some gaffles, and some gaffles have more than 2 decision points between controls. Each variant has a leg which passes a control on a path which is not on their course.
In my opinion, the mini relay needs to be fun & encourage inclusivity. It shouldn't provoke tears & tantrums (in either juniors or their parents). The juniors should enjoy it, and parents need to be confident that their children are safe & going to come back. A TD1.5, pale yellow, course started late in the day when there are other runners around in the terrain they will be running in would allow the majority to come back having run well, the high-flying minority to whizz around, and the less competent minority to challenge themselves, but come back safely. Gaffling is all well & good, but needs to be fair and not over-complicate the courses, or move the planning outside the guidelines.