Considering how best to update our living room (5.5m x 3.6m = 18ft x
12ft) lighting. Currently it is lit by 3 x 60W R80 semi-recessed
adjustable-aim spotlights. R80 seems to have reached the end of their
shop-stocking life & in any case haven't been particularly reliable,
hence what next?

A quick scan the Screwfix catalog indicates that the GU10 (240v) &
MR16 (12v) (+?MR11) seem to be the only contenders (excluding LEDs
which maybe need more development time).

What are the pros & cons?

How do you assess how many units are needed & where to place them in
the ceiling to obtain a good spread of light?

What do the letters & numbers mean - eg MR11 v MR16?

Any advice, esp experiences of anyone doing a similar job, would be
most appreciated.

TIA