Hi there
Welcome to the forum!
The aircraft flying the MAN route also do the LGW flights. The aircraft are either one of the 5 equipped with SuperNova as IFE, which were delivered to Virgin in 2001, or one of the Odyssey equipped IFE planes (two in service i believe) which were delivered in 1997. MAN used to use older aircraft but that is no longer the case, your aircraft will be no different to any of the current flights from LGW (unless of course the plane goes tech and is replaced)
The Odyssey IFE has Nintendo games, sadly SuperNova does not, although it does have a wide range of movies. You can read more about the IFE onboard Virgin aircraft
hereAs for your seats, row 61 is perfectly fine, although if you have small children it might be easier for you if you sat further forward in the plane as the further back you are then longer it takes you to get off.
I hope that has been of some help? If you have any other queries feel free to ask! Id also advise checking out the
FAQ if you have not seen it yet as it also covers a lot of main queries