Try defining "significantly further" and "plenty of fuel". Are you talking 15 min holding here? Longer or shorter? 80 nm or more?
Not sure if you have been out in Canada or you have any ETOPs experience etc but you are not really limited on alternates in the UK compared to those types of operations in those places. I wouldn't say you are limited on most of main land Europe either! That is an opinion though. Contingency fuel is defined in JAR Ops for 3% and 5% along with reserve and final reserve etc. Extra fuel on top of that would be carried if needed due to the wx and other factors. It doesn't make sense to be carrying huge amounts of fuel if not needed though.
I think we essentially agree that you want to find out as soon as possible if a diversion might be necessary and that is all the crew where presumably doing. Reserve fuel for most alternates around LPL and MAN does not change by more that 10% generally at the most extreme for my current aircraft and airline and that includes track distances on arrivals etc. This would only be of a few percent for total fuel required. Only a few minutes flying time difference essentially. Not forgetting you can always contact the ATC for the alternate to check if the is any expected delays for that airport.
Mountain out of a mole hill really.
If the crew made a late call to MAN about the fuel state then I couldn't agree more Route Papa. It would have been Extra fuel if holding was expected though not Contingency and if no holding was expected you can't expect them to be carrying large amounts of Extra fuel. I seem to remember a UK AIC about London TMA and that for fuel planning purposes you should plan to have at least 15 min holding fuel Extra or built in to fuel required can't remember the AIC number or date though. I don't know if it is still current and whether it includes MAN TMA? Maybe with the current traffic growth into MAN, LPL and EMA that a similar AIC could be issued for MAN TMA?