Now I know you are one of us, I might be kinder to you, we have a 70s clique on here,stiff knees and all.
The 5TA does not have a sump plate it has a plug and guaze filter needs 7/16 whit spanner if I recall.
The sump will likely be full of oil, so you need to get that out. As regards the smoking,if its a matter of sumpoil it will smoke for a bit but will clear after a run.
Then again you might have stuck rings; if compreession is low, chuck some redex down the bore for a week.
Modern plugs do not like being cleaned or oiled up. see if you can get some half decent old ones and use those for starting/running till its all clear; and if the plugs you bought have an R suffix, chuck them. Right plug ofr yours is a champion N4 or equivalent.
tappets clearances ok?
taken for granted you have a fat spark? These engines are so soft they should never be hard to start.
As for getting down and under it, some kind of bench to get it up is a must at our age. I have in the past resorted to a block and tackle to lift the things up. [and a bell to call the missus to help me up sometimes].
where-abouts in the country are you?