You don't need any great deal of head for a positive pressure pump and its generally easier to site the pump on the fllor by the cylinder anyway.
As for pumps, I personally (and from experience) would not advise on a Salamander as the seals fail after a few years and on most of their range, cant be replaced. Stuart Turner pumps are higher quality and far better serviced, plus shop around and they can be got for similar cash.
I had a Salamander 3Bar pump for about 5 years and this year it croaked, replaced with a Stuart Turner and its both quieter, more compact and easier to fit.
Oh yes, do it in copper with solder, not the crappy push fit as the temperature and pressure cycling is not got long term on the short cut fittings.
The salamander info is interesting, I hadn't come across many bad reports online (no more than any other brand).
Regarding the push fit, is there any actual basis for the assertion they don't last? The JG fittings carry a 25yr warranty against manufacturing and material defect. My personal (family) experience is a total of about 20yrs of use, 10yrs in parents' house (and counting), 5yrs then 4yrs in two of mine and no leaks in that time.
All the problems I've read about online have been down to poor installs. Namely:
- poorly fitted/missing pipe inserts
- failure to do up the locking rings on fittings
- copper burrs fouling o-rings due to not being cleaned correctly after cutting
As far as I can tell, copper gives only two advantages over plastic, namely:
- for a given outer diameter of pipe, you have a greater inner diameter for water to pass through.
- where space is tight, the fittings are significantly less bulky.
I know the "professionals" don't like pushfit, but then why would they, it turns piping a house from a skilled to a semi-skilled job, so they are bound to extol the virtues of their craft. Then again, around 30-40% of my entire renovation time on our latest house has been spent putting right what various professionals have thought was acceptable.