Any good black out blind companies???

[taytotayto]

i need a black out blind for our babies nursery but i cant afford to get someone out to measure up so i need to do it myself which is fine but who do i go with. has anyone used a good on line company they were pleased with.
also if anyone has any advice re measuring fitting etc i would love to hear from you
thanks x

Ours is from b and q. It was easy for dh (a diy novice) to install and pretty good. There are teeny gaps down edges due to fixing bracket things but as we also have a curtain it's nit a problem.

Our basic coloured blackout blind from John Lewis was simple to fix but as the brackets mean there are narrow gaps of light on each side, we installed thick curtains too. Did the trick. When DD was a tiny baby we had her room ultra dark by putting black out cloth flush against the window pane with suction pads. Now she sleeps really well and doesn't need a pitch black room.