It's a great blog she has, big props to Servonaut for introducing me to it. However, I am surprised that in Tesco she couldn't find disposable cups and plates, although if she was using a smaller branch they may not have had them in stock since the main party season in Christmas and it is a bit cold for outdoor eating. But my local supermarket has disposable cups and plates.
Tortilla chips; that I find that impossible to believe, Tescos have both Doritos and their own brand of tortilla chips on sale. Similarly the sliced cheese and lunch meat, if it is not sold in a pack there will be a deli counter.
Queso cheese; I don't know what that is so I don't know if it is sold under another name.
Salsa she would have found somewhere near the tortilla chips (although it would be in a jar as there seems to be little demand for chilled salsa, people either eat the name brand stuff in jars or make it fresh).
There are some hispanic stores, but the bulk of Hispanic people here are actually Spanish and Spanish food and ingredients are found in most if not all supermarkets. Only this evening did I buy some chorizo picante.

If you want spicier food here you are more likely to go for Indian or Turkish food if you want Hispanic/Iberian/Latin American food we have some Mexican food outlets, but rather more Spanish/Portuguese/Brazilian/Columbian places, for geographical reasons we have very few Mexicans so very little base demand for an extensive selection of authentic Mexican places as opposed to Spanish style tapas bars.