The electoral map is favourable to Labour. They only need 34% to win a majority. Whilst the Conservatives need somewhere from 38 to 40%. So a repeat of the local elections would see a comfortable Labour win.
This poll from June shows that despite the media narrative we hear from the press there are plenty of people in Britain who would like to stay in Europe:
http://yougov.co.uk/news/2014/06/17/eu-referendum-record-leadSo it's not as clear cut as all that. Even if you consider the European elections and UKIPs really strong showing, the majority of Brits still voted for either pro Europe (Labour, Lib Dem, Green [SNP, Plaid Cymru]) or Europe reforming parties (Conservatives)
Labour does however need it's Scottish seats a Yes vote would hurt them a lot more than any other party - though it wouldn't exactly help the lib Dems. Even with both parties losing members and votes at an alarming rate in Scotland to the SNP in recent years, they have far more representatives than the Conservatives who have only a single MP.