T i m wrote:

I'm sure this must have been mentioned somewhere but all of the mini
roundabouts I've checked round here have one entry with double broken
lines (priority?) and all the rest have single?

According to the traffic signs manual Chapter 5 (I haven't
checked if I have the latest issue)

"8.17 Where suitable deflection cannot be achieved, traffic
entering the roundabout might, because of its approach speed,
disregard the standard advisory Give Way line (diagram 1003.3).
In such cases, the mandatory GIVE WAY sign to diagram 602 may be
mounted on the same post and above the sign to diagram 611.1. The
GIVE WAY sign should not be used where it could confuse drivers
into giving way to traffic from the left as well as from the
right, e.g.on the stem of a T-junction or on any arm of a
four-way junction. When diagram 602 is used, it must be
accompanied by diagram 1023 and by the Give Way marking to
diagram 1003 (see figure 8-3)."

So, if I understand correctly, the roundabouts you have seen have
one road where they have deemed it likely that drivers may not
notice the roundabout with a single dotted line, so it gets the
double line and a "Give Way" sign on the same post as the
roundabout symbol.

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.