Siani, I have very similar memories, but I used to prefer onion filling rather than tomato. Actually still enjoy a plain butter and onion sandwich or a simple butter and English mustard sandwich.

Not sure how I came to enjoy these because everyone else in my family thought I was daft. Still enjoy a good old peanut butter sandwich as well, but these days my favorite is tuna mayonnaise or cheese, onion and tomato. Strangely enough, I only started eating tomato quite late in life. Cucumber on the other hand doesn't come anywhere near my plate, not ever.
Never thought of pickling my own beetroot, so will maybe give that a try later today.

Don't try to impress me with your manner of dress cos a monkey himself is a monkey no less - cold fact