Paterson Cousins

Rhea, my niece from Scotland has come to visit us for 4 days with her friend Renice.  It's so lovely to see them and the cousins haven't stopped talking for the last 3 hours... though much of it was about alcohol prices and options at the various places they go to uni...

Here we are eating the lasagne kindly prepared by Martin yesterday.

So what to suggest for a whistle stop (student priced) visit to these parts?  I'm thinking a day in Cambridge (obviously), a day in London and a day in Linton: Zoo, Kitchen... and pub...  Would welcome any other ideas, especially free stuff.