to go back to a holiday company

[MissMillament]

and tell them that a travel agent has offered us the same holiday they quoted us for £200 cheaper. Or is that cheeky?
It is the identical holiday and I don't understand how an agency can offer it cheaper than the company which actually owns and runs the property.

Prices change all the time. Once you have booked you cant really price match as you have booked an agreed price.
Also depends on what costs are for the first travel agent, re fees/flight costs/taxes etc.

I can't see that you have got anything to lose. Don't get your hopes up to high, but you might get a few free perks thrown in.