Refresher training
You definitely need to undergo the refresher training, since your original rating has been expired and does not show on your License. Any ATO will not let you use their aircraft for skills test without having a checkride with them first. Thisis just standard procedure for all ATOs just to make sure that you are safe to fly their aircraft. So that first flight of atleast one hour will easily judge your ability and for them to make decision whether you needmore training or you can go for skills test right after that flight.
Refresher training is determined by the Head of the Training at any ATO, and there are no minimum or maximum hours involved in it. If yu are good enough, the just after one flight, you can go for skills test. Otherwise you may need to do some more extra hours, before the ATO sign you off for skills test.
For CAA purpose, you will be needing a letter from the ATO confirming about your refresher training (regardless of the number of hours) along with skills test report from examiner.