Trailer towing speed limit

Drove to Bath and back via M5 and M40 today. Plenty of obvious holiday traffic on the road, cars loaded up to the back windows with bedding, 4 or 5 bicycles appended to the rear and/or roof, roof box as well.

Many of those that couldn't get it all in or on the car were towing small unbraked camping trailers, the kind that run on 8" wheels.

I'd always assumed that these were subject to the same rules as caravans ie 60 max and restricted to inner two lanes.

Not cruising at 70, and overtaking in the third lane.