(From the album 'THE MUPPET SHOW 2' NSPH 21)
Promo copies of this single list the release date as 11.6.78, but as the 11th June 1978 was a Sunday, this must be incorrect.
Singles in the U.K. in 1978 were released on Fridays, so the release date must be wrong on the promo copies.
Friday 16th / 23rd are more likely to be correct.