请帮忙看下下面中译英的语法是否正确,请修改.

题目

请帮忙看下下面中译英的语法是否正确,请修改.
我们有个核心的工程师要打算去英国考察在12月份,我们希望请你帮一个忙,以你们公司的名义发一份邀请函给他,以便更快捷的获得Visa.
We have a core engineer who need business trip to UK on Dec,2013.We hope you can do us a favor to issue a letter of invitation to him in the name of your company so as to obtain the visa faster.

答案

语法没问题,用词有些欠妥不地道.
核心的工程师 core engineer没这说法 our chief / key engineer
打算去英国考察 who plans to have a business trip
还有 是 in Dec.