Here is what you will do,you can get a class 1 medical from my experiance.
It involves alot of appealing,and you will become a swear word within the CAA,but trust me with this one,its been done by a friend of mine.
You say your just outside the limits.thats good,glad your not waaay out or things might have been a little more tricky.
Now,in the CAA,every time you appeal,you go up the seniority ladder.
Write them a letter,stating you disagree and your appealing;saying your eyesight is only marginal,and see no reason why you cannot operate an aircraft safely.Also challenge them on why the PPL limits are less.
You`ll probably get a letter back..saying no again,and some silly excuse for their reasoning.
Write back,challenge them,stating your appealing;put forward all your arguments...keep on doing this until you get a letter from a doctor with a fancy title,someone furthur up the pyramid.Anyone here know any names???
Then,you are going to write back and tell them that you ARE safe,and you invite yourself to do their eye test,with the chart on the wall with a -5 prescription or whatever the lower limit is,and say if you cannot read the lowest line (2nd to bottom I think) you will accept you`ll not be able to do it and will not bother them anymore,and if you can,your obviously safe enough aren`t you..and therefore if you pass you`ll get a class 1.You passed the test you see...
It has worked several times,go for it,nothing to loose,everything to gain.