Red thing? Steady on. Its an early Eriba Puck caravan with Tiger wheels on, check out hubcaps. Probably has a round lifting roof though it might be an a small oval one. Probably has pointy individual rare rear lights on. The really collectable ones are on 8 inch wheels without windows but these next generation chaps from the '60's are now eagerly collected to create a period combo as they are much lighter than the '70's versions. I suspect it should be cream in colour but it is often a case that the pair are painted as a matched set. I can recommend a Puck to anyone wanting a small period caravan. They are actually comfortable and not like spending a weekend in a folding, leaking fridge that most else offers.
Zundapp looks quite good too. I am unlikely to own another, I think, so my spares perhaps should be sold off to finance buying a Historic racing registered Gilbern 1800 GT. So much better value are these weird old British specialist cars than micros these days. Choice, Sulki on eBay or Gilbern in a shed? No brainer for me. Cannot see much hillclimb potential in the Sulki.