Lets face it. If you are a lib dim then you have prepared your self for a life time of never being in government. You accept the with FPTP you will never get anything like as many seats in Parliament as you should. However due to a once in a generation hung parliament you find your self with a little bit of power. You have been promised a vote on the one thing you want more than anything else (PR or AV). The only draw back is that you have to vote for the SDSR. A bill which at the very least will see the closure of Plymouth Naval base and atleast one of the Moray Firth bases.
Liberal Democrats only have two heartlands. The North East of Scotland and the South West of England. These bases represent the biggest employers in these areas. Even with any form of Alternative voting system FPTP will make up the lion share of the voting system. If you were a Lib Dem MP what would you do?