I have the following formula in a bit of VBA, which works fine:
"=SUMPRODUCT(('0'!$E$2:$E$5000={""Tranche 4"",""Tranche 4 - R0"",""T4
Prem"",""T4 BNL"",""T4 DS"",""T4 SR""})*('0'!$F$2:$F$5000=$B28))"

However, it's a bit unwieldy and I'd like to introduce wildcards so it would
ideally look more like this and thus better accomodate future changes. I soon
discovered that wildcards don't work in this formula!
"=SUMPRODUCT(('0'!$E$2:$E$5000={""Tranche
4*"",""T4*""})*('0'!$F$2:$F$5000=$B28))"

I've had a good look at the many posts on this topic and have tried some of
the solutions but cannot get the right answers. I'd appreciate any
suggestions you may have!

Many thanks