Flexible hose

[gravyminer]

How would I join it onto the mdpe?  jubilee clips won't work there...

I would have thought the plastic insert you usually use would be ok but if in doubt use a copper insert in the mdpe.

And Desp, the silicon pipes on my old scudo van between the turbo and the inlet manifold were only jubilee clipped onto plastic.
Not a vast pressure but hot and oily ........ and the silicon bits performed better than the plastic bits.

[Tombo]

The current arrangement is like this:

The red circle is an elbow, which is about 1 metre below ground level.  I can't reach it with my arms if I lie flat on the ground.  I can only see the elbow if I put my head slightly into the hole (being careful not to lean too far!).  All of the pipes and pump were installed before the finished soil level was known - the tank is about 0.5m deeper than originally expected.

If I'm right, I think Tombo is suggesting something like this:

with an elbow to bring the pipe up to ground level, then a further 2 elbows to send it back down to the pump. 
I quite like the idea of having a semi-rigid pipe going from ground level down to the pump to help me position it carefully on the bottom of the tank, but I'm a bit wary about having so many joints. I suppose two of the elbows would be easily accessible in case of leaks...

I'd probably use the Plasson type of elbow in 32mm rather than push-fit 22mm, though I do have a coil of 25mm MDPE lying around so that would be tempting!

I'm now wondering if this is what Desp was suggesting (3 elbows)... 

What does anyone else think?

Thank you!

Yes that's what I was suggesting.  Although I'd use a T off the main riser at the hi point rather than an elbow. I'd use the vertical connection on the T to fit a tap or vent at the high point.  This could be used for purging air when installing so the pump sinks easily and for testing pressure, flow etc

[acresswell]

Not sure I understand why you have such a large bore pipe to the house.

It's 32mm because that's what the firm who originally sold me the rainwater kit recommended.  At that point I was massively busy at work, so didn't question it. Sadly, I also didn't notice/question how the builder was setting up the connections inside the tank!

I think they recommended 32mm because of the length of run.  Our site is a strange shape, with lots of gradients that limited where the tank could go.  It's about a 25m run round the outside of the house from the tank to the first toilet.  There's also a pipe that runs about 60m to get to our veg patch (it'd be less "as the crow flies", but for various reasons the pipe couldn't go in a straight line)

[acresswell]

Yes that's what I was suggesting.  Although I'd use a T off the main riser at the hi point rather than an elbow. I'd use the vertical connection on the T to fit a tap or vent at the high point.  This could be used for purging air when installing so the pump sinks easily and for testing pressure, flow etc

Another good idea!  Thank you 

[acresswell]

I would have thought the plastic insert you usually use would be ok but if in doubt use a copper insert in the mdpe.

Thank you.  I'm going to try Tombo's arrangement with the semi-rigid pipe first, but will swap the final length for silicone if the mdpe proves to be too awkward...