What do I need to buy to fit a new toilet cistern?

you obviously have a cistern with a flush pipe and not a close coupled one. If you are fitting a china cistern, then you will need 2 brackets to support the cistern as it is much heavier than the plastic one. Your new cistern will come with all new fittings inside which you will have to assemble. Read the instructions and assemble it all, and make sure that the water supply inlet is fitted on the same side as the one you removed. The same goes for the overflow. Do not overtighten any plastic fittings or you will damage the threads and they will leak. Fit the Flush pipe in position, and lower the cistern onto it. Don't fit the cistern first and try to fit the flush pipe after, it won't work that way. You will need a very large spanner or stilsons for the big nut underneath the cistern where the flush pipe fits.

Modern cisterns give a 6 lts. flush. If you have an old WC pan they do not always work with the smaller flush volume. It is just as cheap to buy the whole WC unit from a DIY store or stock line at a plumbers merchant then you know it will work. Easier to fit cos there is no external overflow now. If in doubt get a plumber in because it is not always straight forward. If the system is mains fed then there is often a restrictor fitted in the fill pipe.

Answers to take with you when you go to buy are:

1.is yours a high or low level cistern?

2.if low level is it close coupled?(might not be able to get a china replacement without including pan)

Most cistern kits have high and low pressure valves in them,

most replacement cistern kits are just that and will replace the current ball valve type

All are fairly simple to fit if you have a basic knowledge of plumbing, discuss this with the plumbing shop who 99 times out of 100 will know exactly what you need.

PHONE YOUR PLUMBER AND ASK HIM WHAT BITS DO YOU NEED, if he has seen it he will know- best of luck, he should have told you what you need.

most cisterns come with evrything you need ..as others have mentioned you need to identify what type of wc setup youve got..no cisterns overflow anymore ..external overflow is now banned by housing regulations so all syphons flow back into the pan by design..personally i would buy a closedcoupled pan and cistern as you know it will be a perfect match..and to honest they are not that expencive

all good answers but if your going too get a plumber make sure you get a few estimates because it is nt all that expensive to do what you want only if yer a plumber from hell!

be sure the rough-in is proper size,ie the tank rest on your back wall.

Why don't you simply employ a professional person to deal with it all???