Colin beat me to it
I fitted mine and wrote about how I did it in the Customised link shown by Colin, scroll down from Nigel's OP.
Sargent sell a connecting kit to wire from the regulator into the charging system of Swift caravans
Click Here
When the panel is wired in to the harness you never have to worry about disturbing the wiring if you remove the leisure battery. There is already a connector in your caravan so the connection is just two screws into the regulator and a push on connector to the caravan system.
Roof installation of a solar panel and hard wiring it to the system is not difficult at all, the main things to bear in mind are:
1/ Use a good quality bonding agent to fit mounting brackets to the roof which must be clean and grease free. Fasten the panel to the brackets with sufficient air gap beneath the panel using weatherproof nuts and bolts (stainless steel) so that the panel can be removed if need be.
2/ Ensure that there is no concealed wiring in the roof space where your solar cables will enter the caravan.
3/ Use a good cable entry gland and a rubber grommet and seal for a watertight fitting.
4/ Use automotive cable which is of sufficient thickness to carry the current which will be affected by voltage drop. Automotive cable sizes are deceptive because in most cases the gauge quoted includes the insulation. Use a thicker gauge to minimise voltage drop.
5/ Mount the solar regulator on blocks to allow heat to dissipate.
If you need any help or advice use the link in my signature box to contact me via email.