DCC for Ixion 7mm Fowler

[Itareus]

I've had a trawl round the net and this forum but can find nothing that helps me with this problem, so here goes ...

Have fitted a Hattons 8 pin direct fitting chip to the Ixion 7mm Fowler and the chassis runs fine with this.  But when it comes to putting the top 'arf back on it won't go back on to the chassis but can be rocked gently fore and aft.

Looking sideways on there is a gap (of less than 1mm) when the body is as tight to the chassis as it can be.

My conclusion simply is that the direct fit chip is just a fraction to high, but before I spend a chunk of this week pension on a 'wired' chip I would appreciate any advice on this problem you might be able to offer.

Please be aware that I am useless with a soldering iron !

Thanks in advance.

Chris M