Anne, I reckon you have a Sowerby 2266 (aka English Hob & Button aka Chunky). It looks like a good marigold colour to me; is that right?
Indiana copied this pattern (astonishing really) but mostly every example of theirs that one sees is their iridised blue. It's a very distinctive colour and it has a purpley iridescence. It looks new! Made circa the 1970s.
Adam D has told many interesting stories about the 2266 pattern.
Your other bowl is Imperial's "Shell and Sand" (sometimes just called "Shell"). Yes, I reckon you have correctly identified the colour as their lovely Helios.