My blooms changed colour??!
 

I've been told by users before that my orchid is probably a cambria oncidium hybrid.

I was gifted it over a year ago and when I received it, it had white and pink speckled blooms with some yellow in the center.

I was so excited to see it finally bloom! And to my surprise they're deep crimson and yellow.

I've heard two theories, one is that temperature can affect blooms (I live in a cold part of the UK) another is that because it was a hybrid when there are offshoots/new bulbs from the original parent plant it can go back to its original colour?

It is more likely this is temperature related. Warmer temperatures during bud development often cause darker red coloration in many Oncidiums, as well as other groups of plants, orchids and non-orchids.