Under stairs cupboard

[pigeonbuddha]

Hiya
I'm planning on creating an understairs storage cupboard, as what we have is currently really unsightly as its exposed.
I've found some great DIY instructions here:
http://www.pearstairs.co.uk/under-stairs-cupboard/

My problem is this:
I want to get a professional look and have the structure flush with the staircase but there are some struts in the way.

Untitled

• pigeonbuddha
• 12 Oct 2013
• 1

Untitled

• pigeonbuddha
• 12 Oct 2013
• 1

Untitled

• pigeonbuddha
• 12 Oct 2013
• 1

Are these supporting the staircase or can they be removed?
Unfortunately these "struts" aren't square and so I cant even build the cupboard around them as theyre rounded on their sides.
Any insight would be appreciated!
Thanks

 

[HERTS P&D]

Replace the struts with square timber and build off them.

Andy