Yes, m’Learned Friends like to keep somewhat agreeable hours (apologies, Fred :-)
A little more information for you, SIQ, is to remind you that, whatever might or might not happen with juries, it has no effect on whatsoever on magistrates ("...but rather the inconvenience to judges/magistrates etc. "). Trials in Magistrates’ courts do not involve a jury and the verdict is determined by the Bench of three lay Magistrates (or, occasionally, a District Judge (Magistrates’ Courts) sitting alone).
Your point regarding obligatory jury service is interesting. The alternative to the compulsory requirement arrangements which prevail at present may negate some of the advantages of jury trials. The idea is that defendants should be tried by a panel of their peers chosen at random. The danger in providing a more sympathetic system (where potential jurors can opt out at will) means that the pool from which jurors will be chosen will become somewhat skewed either by age, class or in some other way (in much the same way that arguably the lay magistracy is). Protection exists for those unable to undertake jury duty because of illness or disability and the option to delay their service is available for those with booked holidays or planned medical treatment. But little sympathy is afforded to those who seek excuse on other grounds. My own view is that that is the way it should be. Considerable notice is given and there cannot be too many people who have difficulty arranging their affairs to accommodate it. There is the danger, as you suggest, that some people may be prejudiced (either way) and may not be inclined to determine their case on the facts alone. But I believe the risk of a miscarriage of justice on this basis (there would have to be ten such people on a single jury) is minimal and is well outweighed by the advantages of the jury system.