Driving from London to South Wales

Sounds like a sensible plan.

I hope someone will correct me if I am wrong, but I believe it rhymes with "scow" or "cow".

Yes, Slough rhymes with cow. Ah, this language of ours!

I suppose you could do it, but it is more complicated to get onto the M4 from central Slough, including - depending on where the hire office is (no knowledge) one or more mini roundabouts and one or more full sized ones. More complicated that is than Heathrow locations on Bath Road.

John Betjeman was bang on about Slough. Neither he nor I have any love for the place, except that I like the station where you change from the big fast train from Paddington onto the little one stop branch line tiny shuttle into Windsor and Eton Central.

Nigel, so you believe it would be less stressful for a never-driven-on-the-left driver to pick up the car at Heathrow than in Slough? Could you suggest another stop outside London reachable by tube or train where there might be a car rental office that would be more "on the way" to Stonehenge and lower stress, traffic-wise?

You don't say what the plans are for your entire trip. Do you plan to do Stonehenge & south Wales as a day trip from London or is it the start of a longer car tour?

You could, of course, take the train from London (Waterloo) to Salisbury and then the shuttle bus to Stonehenge. Train fares from Waterloo to Salisbury are expensive. Direct trains also run hourly form Salisbury to Cardiff via Bath. (This service is not running at the moment due to engineering work at Bath. It will resume about 2 September 2015). Alternatively, consider train to Salisbury & then hire car.

www.nationalrail.co.uk
http://www.travelsupermarket.com/c/cheap-car-hire/united-kingdom/

There are other towns on the line you could pick up a car from--Reading, Swindon, Newbury, or if you go from Waterloo Farnborough, Basingstoke or Andover--but I agree with Nigel that it's probably easier to get onto the M4 at Heathrow than most of those places if you're not used to being on the other side of the road.

As you say you've never driven in the UK before, please read the relevant sections of the Highway Code before you do, you may be under the pre-conception that it will be like driving in the U.S. just being on the other side of the road.....It's not.

https://www.gov.uk/highway-code/contents

Good advice about the Highway Code.

It sounds like a bunch of suggestions, but it actually the law that is enforced.

If first stop is Stonehenge then why wouldn't you get a train to Salisbury and arrange the hire car from there?

I would concur with David - if your next destination is Stonehenge, why not train to Salisbury and hire your car there? It saves you a drive.

And Slough ?? Have you seen The Office with Ricky Gervais?

Betjeman later regretted his Slough poem - and on the 100th anniversary of his death his literary estate ran a schools competition within Slough for a counterpoint. The poem was aimed at the consequences of Slough Trading Estate rather than Slough itself anyway.

And within the last week, a number of 1930s "bogus-Tudor bars" have received Grade II listed status.

The train to Salisbury sounds like a great suggestion to save traffic aggravation. But 2 tickets from Waterloo to Salisbury is 76 pounds and 2 tickets from Paddington to Slough (or Burnham, say, since Slough is so despised here) is 18 pounds and the car rental is the same. Maybe Heathrow is the best option after all. Balancing convenience and cost is exhausting! Thanks all for input.

As a followup, we picked up our car at Heathrow as some advised and had no trouble making it to Stonehenge, Glastonbury and Wales, though we did have some navigation adventures, as we were looking for some very specific locations on some very rural, very narrow backroads. All ended well and I feel like I've checked off a minor goal on my bucket list. I would do it again but will consider other options first. Thanks to all for their suggestions.

Thanks for the update, coffee

Just curious, what other options would you consider first? Glad it went (kinda) well.

Bus and/or train, at least as far as Stonehenge. Again, there really weren't any other viable alternatives to a car for our destinations in Wales.