Onthis page of the BA site, in the travel classes menu, select Euro Travller as your cabin type, then in there, in the 'in flight' section you can select seat maps and the 767 seat map is in there.
LCA is currently operated with Eurofleet configured 767s, though these are now declining in number, with only seven left in this config: G-BNWA/B/X/Z and G-BZHA/B/C
This means they are standard Club Europe "convertible" seats, just like you find on the Airbus and 737 fleets, with about 34" pitch at the front of the bus.