Brick Shed and Run Advice!

Hi all, I'm new here so bear with me!

I currently have two seperate neutered males, they grew up together but the people who had them before didn't neuter them when first possible... So as you can probably guess they fought and they were seperated. We have attempted once to re bond, resulting in one latching on to the other and a vet visit

Due to this I have thought about rescuing two females (one each).
Currently they are in a 12x4 foot concrete brick shed, this is split in two, so each rabbit has 6x4 foot inside. They, however don't have permenant runs attached, they do get put out in the nicer weather, due to this rescues wont accept it. Each run is just under 7 foot x 3.5 foot.

I'm struggling to bring the parents round to putting the runs back on the lawn, currently their on slabs, I've looked at using the run around systems, but the 16 foot tunnels aren't long enough, as we have a long and narrow garden, thats slabs, grass and then the rabbit shed. (I'd add a photo if I could figure out how too!)

If anyone has any ideas or advice, it is appreciated, and reading this post back over it is probably a little difficult to understand, but hopefully I'll work out how to add a photo!

Thank you

Most people on here don't have runs on grass, it doesn't last long and they can dig out or predators can dig in. If possible I would make it so they can permanently access their runs, slabs are fine for a run base, you could use rubber flooring or something to soften it.

What Zoobec said. Could you attach the runs that are on slabs for them?

Sorry I realise I didn't explain very well, but the grass is straight in front of the rabbit shed, and a 16 foot rund around tube wouldn't be long enough to get to the runs on the slabs. Wouldn't be putting the little monsters on the grass... I made that mistake when we first had them!
However me and my mum have ganged up on dad, and he is now (kinda) willing to give up the small bit of lawn to put slabs on top of, so then we can attach tubes to the runs!
So we may have sorted it!
The things animals make you do eh!