Deanors200mk6

Right so we have just four our mk6 rs2k back on the road after quite a while. When we put the engine back in it would not start.. just a click everytime you turned the key... replaced the battery and it went.. the next day click click.. replaced starter fine for a few days then click.. we have clean all the earths and still has the issue... sometimes it will start fine then sometimes has this issue..

Thanks in advance