The policy - insofar as it exists as a conscious policy - is also ad hoc because the principles behind it that are on display, aren't really backed up with action after the symbolic move has been taken. Though the Tories have tried to present the ECR Group in the European Parliament as the "first real opposition" and the separation from the EPP as the opportunity to give people a chance to vote for a sceptic, non-withdrawalist grouping, scant attention has been paid to the ECR apart from its scandals (of which it has quite a few for such a young party). In fact, the Group doesn't even have it's own website - this was brilliantly exposed by Jon Worth's cybersquatting. But then, the aim was never to advance a political ideology, but to bin Europe as an issue in the Tory party altogether. The move to the ECR will therefore result in a loss of influence in the European Parliament, while not advancing any clear political vision. It has also started to damage relations with former EPP sister parties like the CDU - as the BBC reports:
"Joint policy groups have been scrapped and an annual meeting has been cancelled. [...] Mr Altmaier [from the CDU] acknowledged that the working groups had concluded their work, but added that when the time came to form new ones the CDU would be looking to their partners in the EPP. [...] He added that, for the same reason, no Tory MPs had been invited to come to Germany as observers during the recent election campaign, as they usually would have been."
Though pragmatism will mean that the UK won't be completely isolated in the Council under a Tory government, the Tories will have to work and lobby harder to construct issue-by-issue alliances.
The promise of a referendum over the Lisbon Treaty brings the Tory dilemma over European policy to a head (though it naturally won't be resolved given the dangers the issue poses to party unity). Since the UK Parliament has already ratified the Treaty, it would be an incredible reversal of UK foreign policy to push for its retrospective rejection in a referendum - especially if the Treaty has come into force. Tearing up (or attempting to tear up) a painstakingly negotiated compromise is also unlikely to help with mending fences after the EPP split. Perhaps most importantly for Cameron's likely government: it would also open a can of worms for the Tory government - with no clear party vision on what it wants out of Europe, and with the fragile unity the party has on Europe, can a Tory government seriously renegotiate a relationship with the EU that's: (a) acceptable to the whole Conservative party; (b) acceptable to the other member states; and (c) legally and practically possible? And that's without taking into account the vast economic problems the Cameron government would have to face, as well as the questionable populism with which the Conservatives are approaching constitutional reform in general.
So what's Tory policy towards the EU if the Treaty is in force if/when they come to power? Either there's a referendum on the Lisbon Treaty or on EU membership, or there's an attempt at renegotiating back competences, which would require a clear idea of what exactly the Conservatives want, and what they think the EU is for. It would have been better for Cameron if Ireland had voted No and taken the flak for binning the Treaty, so that the Tories could advance their aims, such as they are, without a loss in diplomatic, political capital and party unity. But now Cameron has to make a choice.
At the heart of the Tory dilemma is that it wants to see reform the EU, without exactly knowing what it wants from the EU. Presumably withdrawalism, though vocal in the form of Cash and Hannan, remains a minority opinion in the party since the ECR is more geared towards retaining and advancing the single market aspects of the EU while supporting deregulation and reversing integration. Yet the die-hard anti-EU wing of the party has managed to exert considerable influence on European policy, because the withdrawalists are the only wing of the party that have a clear vision of the UK's relationship with the EU and also enough momentum in the form of the policy concessions they've won from the party leadership to drive their agenda.
Cameron effectively lost control of European policy from day 1 when he promised that the Conservatives would leave the EPP, since he can't push for a more moderate form of scepticism. This creates real problems for him, because the belligerent style of current Tory policy makes progress on even moderate aspects of Tory European policy almost impossible to achieve. The European question won't go away - time won't solve this one. Splitting from the EPP means that Cameron can't hide from the European question by just muddling along as before. Cameron has signalled a change in Tory policy toward Europe, even if substantive change wasn't intended, and with little control over the expectations his party creates, Cameron is likely to be dogged by the issue if he can't deliver.