I found this item on eBay. Is there any company in Ireland offering a service like this where you can buy blinds for a "standard" window - or indeed trim them to size?
The homebase/B&Q/Atlantic Homecare would all sell blinds for standard window sizes fairly cheaply. Not sure about the 'trim to size' aspect - I'd imagine these would never really work out to be as neat as 'made to measure'. We used 'click for blinds' on the net - polish company - cheaper than getting made to measure here, and good customer service.
No affiliation with them - just satisified customer.
I've seen ones in the Argos Catalogue that you can trim to size. They also do other blinds in standard sizes there which look quite nice.
Are you in Dublin??? If so there's also a blinds shop on Capel Street (towards the Parnell Street end I think). These look better quality than the Argos ones and they seem to have a good variety there.