June 19 (Reuters) - Downer EDI Ltd DOW.AX
* Encourages Spotless shareholders to accept offer promptly and without delay
* Refers to its takeover offer through Downer EDI Services for all of issued shares in Spotless Group that it does not already own
* Offer price of $1.15 per spotless share is final and will not be increased in absence of a superior proposal Source text for Eikon: Further company coverage: DOW.AX