Filling sealed heating system. Do I need a flexi pipe?

In article , Rob writes

I certainly wouldn't do it without a double check valve in place plus you can get filling loops, with DCV, two taps & flexi for just over a fiver so using the official thing doesn't really hurt that much. Worth a fiver just to avoid the tutting from the technician when you have it serviced/repaired ;-)

Very true. Also the rason you connect it to the mains is to use the pressure of that to fill your system. Does your pumped spring water provide say 2 bar of pressure (20m of head) at the point you want to fill the system?

It provides up to 10 bar. Depends what I set the pump and pressure vessel to!

Thanks for the advice anyway. The flexi loop things are only a tenner in B&Q now it looks like BES are charging postage on under 40 quid orders.