Wolseley 27" restoration

Hi All

I have just joined the club as I have recently been given an old mower as a summer restoration project for me and my son, post his GCSEs.

After some online detective work it turns out to be a Wolseley  27" 'Limited Edition', with a Briggs 170702 engine, circa 1972.

I have managed to get hold of a original parts list and diagram book, which has been useful for the strip down. Most parts appear to be in reasonable condition considering it has been in the back of an old hay barn for the last 25 years. The only obvious problems being a broken drive shaft out of the gear box to the rear wheels, and a perforated fuel tank. A local engineering company can turn up a new shaft for me, but at the moment I am struggling with the fuel tank. It is mounted on the mower frame but looks very much like a Briggs. I have found a smaller one online, but cannot seem to find the exact size. It is approx 14.5" L x 5.5"W x 6.5" high. Can anyone please help?

Also, any guidance on what to repack the gearbox and axle differential with? I have some semi fluid grease in stock that I was going to use! 

Assuming we can get it  up and running again, what is the thinking on a full restoration of the paint work, decals etc versus leaving it in its rather tatty original attire?

Thanks in advance for any help or advice for a couple of enthusiastic novices!!