Please have answers below in bold green ( same text of your email):
After waiting patiently to purchase off plan for 3.5 years, a property which should have been completed 3 years ago we have advised our solicitor to withdraw.
He has asked for power of attoney to do this and sent a "general power of attoney" - we are uncomfortable with this due to the extent it enables him to exercise in our absence. Is this an unusual request? It is not unusual but it does not mean it is advisable.
What steps does a lawyer need to take to get our money back? We have had 2 guarantee's from the builders bank, the last one ran out June 08 and they have failed to provide a fresh one! No problem about expired Guarantees: http://www.costaluzlawyers.es/index.php?page=bank-guarantee&hl=en_GB
The process initialy consists on an initial attempt for amicable refunding and it failed, an excution of the Guarantee in Courts.