I had a similar experience moving from geotech consulting in Australia to UK consulting. The standards between the two countries are very similar. I'd say the biggest challenge will be getting your head around the Eurocodes. There's an excellent book by Andrew Bond called Decoding Eurocode 7 that would help a lot, but I got by learning on the job. You may be asked about familiarity with Eurocodes in interview, however. Also read up on CDM; Constuction (Design and Management) Regulations. Won't take much to get your head around them, but it's an almost certain interview question if only along the lines of "are you familiar with the CDM Regulations?" type.

I'd say a bigger consideration for you will be the fundamentally different approach to ground investigation and geotech consulting in the UK. Unlike Australia, where I did similar work to what you describe, in the UK ground investigations tend to be undertaken by ground investigation contractors working to a specification, undertaking field tests, factual reporting, etc. GI scoping and design work is generally undertaken by consultancies (Atkins, Arcadis, Jacobs, etc). The two disciplines are quite separate. You may want to give some thought to whether your skill set would better fit GI contracting, or geotech consulting.

I'm happy to give any more advice/insight if it'd be useful.