Pumps should last near enough the same wheather using 6 or 8mm, they are up to the job IMO.
That's not the issue for me though.
Power consumption & pressure are the two main factors for me & is why I use 8mm hose. Virtually zero pressure in system & my pump runs at tick-over ( number 1 on a digital varistream) to give a good flow. I can run it direct from van battery (45Ah) all day too.
What we all need is a hose which is 11mm OD / 8mm ID. Alex? 
You are right - a flow controller will reduce the drain on the battery which is very useful and will probably prolong the life of the battery.
I will send you a sample of the 8mm ID hose we have on the shelf - you might find this close enough to your size requirements. 
I'm using your hose Alex
Bought it last year unless you've changed it since?
Cleantech used to sell 8mm hose with an approx 11mm OD, you could get 100m on a 50m hozelock reel. Mine lasted about 4 years without issue. It was superb, just like microbore but with 8mm ID.
There is a company selling 8mm ID x 11mm OD but I'm not convinced their website is correct. I emailed them to confirm but got no response.
The ultimate hose it would be.
