Question: I have just discovered that you can do both a combined smart contract that includes both the token and the crowdsale OR have the token in a separate contract from the crowdsale contract.

Can anyone tell me what the advantages are to either of these methods please?

Many Thanks,

Phil.

Answer: 
If your contract costs that much, then you must be doing a bunch of storage initialization. Storage, by far, costs the most to read/write.

The irony of Solidity is that it costs less to redo things in memory, so if you have some variables, you can re-initialize and recalculate. It's probably better to do so in memory each time a contract method is called.
This is not the answer to the question, but I would like to add this to the previous answers.

When you commit your transaction, Ethereum client calculates, how much transaction would cost if transaction uses all provided gas up to gas limit.

So, if you have gas limit set to `6,700,000` and gas price set to `20 gwei`, then client would require you to have at least `0.134 ETH` on your wallet. I am unsure if it is possible to disable this check.

You can try lowering gas limit for your transactions or gas price, but this would cause longer confirmation time