Raleigh Pioneer Mountain Bike S/N P7545127 Age? Seat Post Diameter?

Hey All,

Thanks for the platform!

I am rehabbing a Raleigh "Pioneer" Mountain Bike with S/N P7545127

I've been on a few sites, but can't find any info for a Serial Number that begins with a "P".
Any ideas about the Age?
The individual that had the bike before me sawed off the replacement seat post and it was too big.
Hoping to find the Seat Post Diameter? It is looking like a 25.4?

The bike is steel frame.

Many thanks!

Tripp