Hi Cath!
Sorry no one got back to you- most of us are North Americans so your posts went up at 1:00 am and 9:30 am give or take an hour or two depending on our time zone.
We were, indeed, sleeping on the job.
Broder looks pretty easy to work with- I'd guess that you could hacksaw those supports to the length you like- you might want to use single units so that your shelves go all the way to the desired height- if you use one of the multiples that share uprights, you'll have to make some compromises about height to get shelf support. Hope that makes sense.
Remember with hacksawing, you just keep at it. You don't have to be Hercules, just really persistent! Buy extra blades!
HTH,
kelly