Gareth uses TradingView for viewing charts, but it is not a broker.

Some big name platforms for trading cryptocurrencies include Coinbase or Coinbase Pro, Gemini, Binance, Kraken and/or Kucoin for crypto trading

Kucoin and Kraken can short crypto.

Please contact brokers directly with further questions to find out which one is best for you or how to execute trades, etc. as each platform is slightly different and things can change over time, therefore it is best to contact them directly. Thank you.