thanks for the replies so far, still unsure

Frogs
I don't know a lot about frog habits. My rear garden is completely closed in with no gaps and 6ft fences. How high do frogs, or toads, jump?

Cats
I have no cats (they died several years ago ) and the chances of an unknown cat dropping a present in my front and back garden with only the frog spawn getting into the pots (with no random limbs or innards remaining elsewhere), on two separate occasions, is a long shot.
Given my memory of frog spawn from younger days, it is a mass of jelly globules with a black or dark dot inside. http://upload.wikimedia.org/wikipedia/co...gspawn.jpg

This is individual lumps of clear jelly stuff, quite angular and solid, like chopped up sweet jelly for puddings and trifles etc

Manna
Michael, you must come round to dinner

Blobs
Lottie, I know the red blobs you are talking about and have seen them ages ago, when i was young and living in the country, on damp/dead tree sumps. It's not them, but they are very curious.

Snails
Waaaaaaaay to big and solid for snail or slug goo. i recently set a gymkhana for snails etc in my garden hours of fun.

The best likeness to my jelly quatermas is in the first few seconds of the video on the link.