okay.
thanks for all that. i had just about settled on the straight lengths already, it only makes about a fiver difference to the price anyway as long as i can make the joints work out in the right places so i dont see much advantage to the coil. and as has been said, coils cans sometimes want to bend a bit. interesting point about the connections; nice to know they cant accidentally pop apart when you rummage in the back of a cupboard.
but on the whole not much to choose either way then - each has its own advantages and hang-ups.
and price diffs are marginal really when you take into account the pump, calorifier etc.
one further point though - the pumps seem to demand an inordinate amount of lecccy - over a total run of 30 metres is it at all likely that 33amp thinwall cable would be enough or should i play it even safer and go for silly amperages? just top of the head ball park opinions will do. i've already done the math but the info on pumps (shurflo 11.3lpm 30psi that draws 5Amps max flow and a 7.5 Amp fuse) leaves me wondering if i'm right (yes, i have checked more than once)
thanks for all the help on this one - i'll be back with q's about leccy matters later
cheers
nigel