Looks nice Ken, well worth saving, I like those Ariel brakes.
Your troubles are not unusual, no disrespect to the machines but many have had a hard life or been poorly maintained / done up by previous owners.
I joined on here after a similar purchase knowing very little about the bikes apart from the fact I loved the idea of owning one...I've been through the gear box, primary drive and top end now over about three years oh and most of the cycle parts... in fact pretty much everything apart from the bottom end which is unusual fingers crossed.
You will learn a lot tho and there is huge amounts of information and encouragement to be found on here so welcome and get those sleeves rolled up!