Locating the bath
Stand the new bath in position and adjust the feet to the required height. Make sure the bath is level. Mark the wall to show the position of the taps and the new waste outlet.
Remove the bath.
Extending hot & cold pipes and waste for the bath
Extend the waste and supply pipes to the vicinity of the marked taps and waste outlet. These should terminate in a location which will still allow you to reposition the bath, but also afford you access to making the final connections. This will prevent the need for you to squeeze your hand between the bath and wall and fiddle with awkward connections.
Assemble the taps and waste
Assemble and fit the waste outlet for the bath. Follow the manufacturer's instructions regarding the position of gaskets and/or use of sealant. Assemble the overflow pipe. The systems for these vary, but they generally connect back down to the main waste point.
Insert and fix the taps again following the manufacturer’s instructions. If the taps have tail pipes with them, shape and fit these.
Otherwise, cut a couple of lengths of copper pipe to make your own tails. These should be gently shaped, and long enough to ensure that their connection to the supply pipes can be made in comfort. Fit these to the taps using the supplied tap connectors.
Connecting the hot & cold
Move the bath into position and check all pipework alignment before securing using the recommended fixings.
Connect the tails which you fitted earlier to the supply pipes. It is generally best to use compression fittings to do this. Use of a blowtorch next to a plastic bath is asking for trouble!
Consider using in line isolating valves for the final connection. These will provide a means of switching off the water supply in the case of leaks or for maintenance.
Connecting the waste
Connect the trap to the waste outlet and to the waste pipe. Where space beneath the bath is limited, a shallow trap may be used. But, in this case, the waste must go to a gulley not to a soil stack.
Before fitting a side panel to the bath, switch on the water supply and check all work for leaks. This should include the waste.
Don’t forget to check the overflow as well by filling the bath.
It is a lot easier to discover a leak now on the overflow rather than relying on a wet ceiling below to tell you.