These are the two hardback UK annuals, published in the UK, based on BATTLESTAR GALACTICA.
Both are, technically, based on the faux feature films rather than the TV show (which didn't reach British shores until 1980) itself.
These contained all-new material (a mix of strips, text stories and articles) which make them the THIRD contemporary strip interpretation (after Marvel's and LOOK-IN) of the show.
The second annual, as the title suggests, ties-in with the second Battlestar movie, released in the UK in 1980. There's actually very little inside specifically related to the film. For some reason, CONQUEST OF THE EARTH was never deemed worthy of a third edition.
For the benefit of overseas readers: annuals were (and still are: after going through a slump during the nineties, they seem to be revitalised today, albeit mostly aimed at a younger and - apparently - less demanding readership) hardback children's books published around this time of year and pitched mainly at the Christmas gift market.*
By the 1970s/ 1980s, the majority were based on media properties (film, television and comic books) and - occasionally - the latest pop star of the moment.
Many of the annuals based on licensed properties demonstrated a most tenuous grasp of the source material, either because it hadn't reached the UK yet (deals had to be signed, and books produced, months in advance. Publishers didn't always know much about what they were publishing... or whether it would actually sell) or because the creative team assigned to the book didn't care much. The DOCTOR WHO ANNUALS, from World Distributors, were notorious for this sloppy quality control (and they were produced by a UK published and based on a well-established TV show. Sigh).
*My birthday is this month so my wish-list always included as many annuals as I knew were available in early September (WH Smith and larger branches of Martins would always allocate a whole table, from the end of August onwards, to that year's wares) with a mop-up operation (for late arrivals and anything outstanding) at Christmas. Typical fare on any given year would include EAGLE, BATTLE ACTION FORCE, STAR WARS, 2000AD, JUDGE DREDD, TRANSFORMERS and anything that tickled my geeky fancy.
Most retailers, desperate to ditch stock, would heavily discount any remaining stock straight after Christmas which was the third (and final) chance to stock-up on left-overs. I have a strong memory of scouring the local branch of WOOLWORTHS (R.I.P) on the first trading day after Christmas looking for that year's elusive STAR TREK ANNUAL (assembled from creaky Gold Key reprints)... and finally finding it in a stack of about-to-be-reduced books in the corner. I went home happy that day.
I acquired my copy of the first BG annual years after it was published, but I distinctly remember where I found my copy of the MG:TCA edition. There was a run-down shop, on the corner, of Chelmsford High Street which (amongst other things... mostly books, stationary and - maybe - pocket money type toys) had direct-from-the-printer boxes of remaindered annuals. I got, although possible not at the same time, this one and the STAR TREK: THE MOTION PICTURE Marvel/ Grandreams annual. That shop disappeared decades ago: the dilapidated building was renovated and (for many years) housed a large branch of newsagent/ bookseller John Menzies (so many a geek purchase was made there) before the chain was taken over by rival WH Smith and surplus branches (including that one) closed. Now, as far as I know, its a branch of Next.