M25

The most direct route (shortest) would be to plough straight through London which apart from being difficult to follow would take about twice as long.

An alternative to the M25 would be to take the M11 to the North Circular (A406) to the A4. This is about 15 miles shorter and probably around the same time. The foreseeable risk with this route would be a major event in London on the day, such as at Wembley.

Australians are entitled to a deep discount for congestion zone fees on Sunday by international protocol.

The other half of the protocol being that Brits may dive on the left within the ACT on Sunday without penalty.

No matter which way you slice it you have a long hard slog for that drive. What a shame that your two points are so remote, and that you are using a car.

Braintree into London by train is a piece of cake, as is London to Heathrow.

If you take the M25 it is probably the fastest, even with the many miles of roadworks on the Essex stretch. In the roadworks are speed averaging cameras - you get a ticket if you offend any one of them or if you are found to have exceeded the limit between any pair. The speed limit is 50 mph, strictly enforced. When you see the variable speed limit signs illuminated elsewhere on the M25, especially as you pass the M1 on the way to the M4 you are likely to see them, and they have cameras behind the signs.

I have seen the North Circular turn into a parking lot more times than I can count (although marginally better than its brother south of the river) on a Sunday, especially around Southgate and the the quadrant between the M1 and the A40, with Staples Corner always providing additional entertainment.

Going through central London will take ages. A few weeks ago (for reasons too complicated to explain but involving campanology) I had to drive from the City to Waltham Abbey on a Sunday and decided to use the east end A roads. It took over 2 and a half hours.

At least on the M25 you are likely not to get lost.

BTW - no congestion charge on a Sunday, but the M-F congestion charge has just gone up to £11.50 if paid on the day or double and skyrocketing if not.

It is noticeable that drivers on British motorways invariably stick religiously to the 50 mph limits in road works, while they are normally more cavalier about the general motorway speed limit of 70. I don't know if this caution comes from the experience of getting caught by the "average speed" cameras or not.

Have you been in my back seat, Bob?

Bob, they stick to the speed limits in the roadworks because they nearly always have cameras. Where no roadworks exist, most regular users know where fixed speed cameras are located & also the favourite hide outs for the cops!

AVOID the North Circular at all costs...it is one of the most frustratingly congested roads I've ever driven and I'm from the Los Angeles area. Part of it is like a freeway and part of it is like a city street with nowhere to get off. Nightmare traffic! Just stick to the M25...yes it's longer but it will be faster and far less stressful.

Thinking about the timing, there are total and partial weekend closures of the A4 Hammersmith flyover until early August which won't help traffic in general in west London. Mary hasn't indicated when her journey is to take place.

Thank you all. We will stick to the M25. We will be there late July

By late July the Hammersmith closure is westbound, the direction you would be travelling.

But if you stay on the M25 the Flyover issue won't directly affect you.

Looks like you're set. Happy motoring!