If you like. I’m easy.

I’m away until Monday, my bro is holding down the fort, but If I order and he receives on my behalf he might start to party in the jungle without me.

Pretty much all coins vary in value like stocks do. There is finite supply of coins based on mining, which is using processor power to solve pieces of the block chain which gets more difficult as it progresses. However no matter the amount of coins that are availible if they are not wanted then the price goes down.

Often times certain events influance the demand for the currancy. The reason it went down this time was due to a Coinbase announcement that they where not going to be allowing BCH trades for a specific period after the hard fork that happened just recently. A big BTC holder sokd off a shiload of coin which started it to drop and of course others started following suit and sold off their coin as well. There are also things like market corrections, people pulling out to invest in stock or alt coins and a bunch of other random shit. Some of which is predictable and others very much not so.

Hope that kinda sumarizes things.

Shouldn't that coinbase announcement help BTC as it's a substitute for BCH?

The cryto world is even more fickle then the actual stock market. CoinBase is one of the biggest market places / sellers of crypto so it put a lot of people on edge. Been downward a lot since then.

I noticed my wallet went down a couple days ago, the pound happened to drop at the same time, is this just purely coincidental?

Supply and demand. Not being short here but every price comes down to that.

OK what determines supply and demand?

Supply is limited by mining difficulty so it's always growing at a slower rate. Basically coins are getting harder and harder to mine.

So the bitcoin value should be increasing not decreasing?

Demand is another matter, who buys bitcoins? Besides biggaz? Speculators, "fin-tech" traders of every size and shape but they all look for one thing: a quick profit. Their dealings amongst themselves is all game theory and meme-pumping. So lots off ups and downs.