Since you do not have an EU issued, or an EU converted licence, national laws will apply. If you intend to drive in France this means:
If you come to France for a short stay (for holidays, for example), you can drive with your license. It must be valid and be written in French or accompanied by a translation or an international permit.
For Germany you also need it to be translated:
When staying in Germany on a temporary basis (e.g. as a tourist), you are permitted to drive a motor vehicle if you have a valid Australian state/territory licence together with an official translation into German.
So while you don't need to have an IDP, you need to have some kind of official translation of your licence to both French and German. (I haven't checked the laws of Belgium and the Netherlands, but if you're trying to get from France to Germany using those countries I guess similar laws would apply, and you'll need to have a Dutch translation as well). I'm not sure where you would be able to get those translations though.
Note that these are what you should do officially, in practice an English language licence is usually enough to drive in the EU, but you won't be able to count on this if you encounter a strict police officer.
Note that if you intend to stay in the UK for long term, you should definitely convert your licence to a UK one. You can still drive your car while the conversion is in progress (as in the UK you don't need to have your licence with you while driving), and you'll be able to use that licence easily while in the EU. Note that your converted licence is still only valid for short term trips in the EU! You have to do the conversion while your licence is valid, and within the first 5 years of you moving to the UK, after which you would need to retake the driving exam.