[wbmkk]

As a new allotment holder I have been watching a few YouTube videos.

One gardener always sows 2 bean seeds in a pot and then just plants them next to a pole at the end of May

This sounds a good idea, but I thought I would ask in a forum, rather than relying on one person's idea.

Is it OK for runner beans too ?

[Hampshire Hog]

Probably depends on how close your poles are to one another.
I normally plant a bean seedling and also pop in a seed as well to provide some succession and guard against failures. You can obviously overdo things but if you have a good amount of moisture holding compost I don’t think you should have a problem.
Cheers HH

[Mr Dog]

I always do (and the same for runner beans). I space the poles 1ft apart in any one of a circle for a 6 pole wigwam, or in an 8 pole 2ft x 2ft square arrangement or in a double 'A' row with approx. 2' between the rows. All work very well, although now that I've built a more permanent support structure I will be using the double A row going forward.

My neighbours still trench and fill with waste over winter for their bean bed but I find that I get equally good  results from a generous sprinkling of chicken manure pellets around January time.

[New shoot]

One gardener always sows 2 bean seeds in a pot and then just plants them next to a pole at the end of May

I always do this as well.  Mine are in plot soil, sometimes over a bean trench, sometimes not, but always with a sprinkle of pelleted chicken manure.  Works just fine 

[AnneB]

I do the same.  This year I have wigwams but last year had a long row.  One seed sown on each side of each pole.  Works fine and makes best use of space.

[Auntiemogs]

I often put 3 small plants in together (planted in bottomless flower pot for added protection against slugs/snails), and they seem to be fine as long as they're fed and watered. 
I never thought about poking an extra seed in the extend the cropping time  , so thank you HH for that! Might try a 2 + 1 this year. 
AM