Anyone got any ideas what i should do about the following.....

Between 1982 and 1985 I attended college to get a BTEC certificate. As an apprentice with British Telecom.
In 1985 i sat the exams and failed the final maths exam i resat this exam and then passed.
I had the slip of paper that was issued by the college to verify the grades attained in each subject but the BTEC certificate was never sent to me.
Unfortunatley over the years moving from house to house i have lost this slip with the grades on.
As i am now planning to Immigrate i contacted Edexcel to get a certificate issued they now say that they have no record of me.
I contacted the college and they have said that they destroy all records after 10 years. Although Edexcel said that they would issue a certificate if i got the college to present this slip to Edexcel.
I can get a letter from BT to say that i actually attended college for the 3 years but they cannot verify the grade that was attained .
I really dont know what to do, anyone been in a similar position.