Suitable a levels for a degree in engineering

DS, who wants to do engineering, will do maths, further maths, physics, chemistry and 3D design.

It depends on the engineering - if he wants to chemical or biochemical or biophysical engineering them obviously chemistry and biology are relevant.

If he wants to do mechanical, electrical, civil etc then chemistry is not that relevant.

For all maths and physics and probably further maths (with an emphasis on the mechanics bits) would be best. I think English is the least relevant to be honest.

Also consider universities that specialise in engineering - the Uni I work at does no engineering courses, the one I did my degree at was almost half engineering courses. It makes for a very different feel to the place.

Yes, DT a good option after Maths, Physics and perhaps Further Maths - see Russell Group Informed Choices where DT specifically mentioned for general, aeronautical and mechanical engineering.

Maybe that came out wrong, didn't mean to sound dismissive of English! FWIW, I'm an engineer who did a 4th arts a-level because I enjoyed it :) but Oxford may well make an offer explicitly excluding particular subjects, so if OP's son is set on Oxford he needs to choose his subjects wisely.

Ideally, maths, further maths and physics. The other subject isn't as important, plenty of students have a subject that's unrelated, but a lot of people do choose chemistry. I don't think DT has any particular advantage over chemistry. Why is he planning on taking English rather than further maths? Even if he can get an interview/offer from Oxford without further maths, it'll be a much easier transition to study there if he has it. Realistically, the course is very much applied maths, and the vast majority of applicants will be taking further maths :)

DS is taking resistant materials design technology as one his 4 A2s to study mech eng at uni. It's certainly useful for some disciplines, less so for others. But maths, maths and more maths should be his focus.

DS1 is now in his second year studying aero eng, he took maths, FM. Physics, chem (and geog to AS).
DS2 is taking maths, FM, physics, res mat (and chem to AS)
At DS uni, anyone with less than AS in chem had to take additional chemistry modules in the first year to bring them up to an appropriate level, but it doesn't follow that all unis or all courses insist on that!

Most important thing is a really good grounding in maths. If he can do further maths that will really help.
Which sort of engineering?

Which type of engineering matters a lot, I would have thought.

DH did physics math & DT. On to electrical engineering.

my nephew is on an engineering course. he did triple science and maths at 'a' level. didn't do too well in the first year so has transfered to doing btec in engineering at college and is applying to start his degree in sept 13.

just saying 'a' levels aren't the only option

Generally you need maths and physics for engineering. Chemistry not so important. A quick look here tells me that Oxford want both maths and physics and preferably also further maths.

At other universities it might depend on which particular area of engineering he is interested in, so you would need to look at specific degree details, or speak to admissions tutors (who are generally quite helpful and responsive). Civil engineering at UCL has no specific A Level requirements - you can go in having not done maths or physics even.