At the moment im using a Jaycar KA1732 kit but its not quite what Ineed: settable counts between 1-500 and settable wait times between each relay activation of 1-60 seconds.
That device has the following schematic (which I pulled from this link archiving the March 1991 copy of Electronics Australia):
Image may be NSFW.
Clik here to view.
The author(s) suggest the idea of using a rotary switch to match up the CD4020 outputs with the BJT base.
How easy would it be to modify this kit to meet my requirements
Not easy. The schematic has a 555 timer, which may be useful. But it also uses a CD4020, which isn't readily usable for your needs. And finally it includes a simple circuit to activate the relay -- which may be useful. But the CD4020 provides the core functionality which differs fundamentally from your own needs.
or would I be better off programming an arduino to out put what ineed?
An Arduino (or Raspberry Pi) would likely be over-kill. However, there's lots of educational and library support for them. And learning to program them is about as easy as it gets. Also, it's quite likely that you can find an add-on board (shield) with relays that you can directly use, too. So this may be the fastest way to get what you need done.
More, you likely can get all manner of nice ways to enter your 1-500 and 1-60 numbers -- even up to and including a keyboard and a display like a PC has. So it can be pretty fancy.
You could also consider the idea of modifying the board you have so that it uses a microcontroller to replace the 555 and CD4020, while keeping the relay and its driver circuit. But here you would be deeper into the programming weeds, so to speak, and you would still need to come up with some way of setting your 1-500 and 1-60 numbers.
In summary, I think there are at least these three directions. (1) Develop your own complete logic system (without writing any software or using an MCU or Arduino or Raspberry Pi) and replace the CD4020 with that logic system; and (2) Assemble an appropriate set of Arduino or Raspberry Pi hardware and learn to write your own software and use existing library code to get the job done; and (3) Consider details needed to add a tiny MCU to the existing board (also replacing the CD4020) and learn to write embedded software for it.
In all cases you will have to come up with a way to specify the 1-500 and 1-60 numbers you want to use.
